I want to call out one thing in case you didn't know.

The idea of a public VPN is to hide your traffic with other users who also use the VPN. If you're renting a VPS you don't get all the "benefits" of a public VPN. All you're doing is adding an extra hop to the internet, you're not mixing your traffic with others using the same IP. It's all you.... In fact, you're probably making it easier to isolate the things you do online because at home you could say a guest you had over must have downloaded it. If its the VPS, its all you.

As mentioned in the comments, the VPN isn't really viable here. That being said, your DNS iptable statements don't work for two reasons:
1. TCP 53 isn't going to be used unless something like EDNS or zone transfers occur which is like never.
2. The first statement blocks any traffic on the output chain (leaving your network) that is destined to a remote UDP port 53. This kills your access to any off-device DNS server.

You would have to have an ACCEPT statement to allow the DNS traffic through the VPN. Something like:
iptables -A OUTPUT -o tun0 -p udp --dport 53 -j ACCEPT

Why do you think that a VPN isn't viable?

I don't understand it, why doesn't these commands block internet access when they block DNS traffic like the ufw command?

The problem here is that it sounds like you think torrenting traffic is using the self-hosted VPN, but that wouldn't be true.
Here is how it sounds like it is currently working:
Torrent Client -> VPN interface -> Default interface -> Torrent Users
You could probably confirm that with mtr/traceroutes and bmon.

The reason your internet goes done when you run your iptable statements is because you're preventing DNS resolution which uses UDP 53 from leaving the device. Even if you are running your own DNS server on that VPS, unless you have trackers' statically mapped, DNS recursion has to be allowed for your VPS to determine host IPs.

Nope, I checked the traffic with mtr and it connects directly to the internal IP address of the server. Also I've bound the torrent client to the network interface of the VPN to ensure the traffic goes through the VPN.

I understand. The problem with the rules above though is that it would block my regular network interface even after the VPN goes down. That's why I created some postup and postdown rules for the Wireguard config.
PostUp = iptables -I OUTPUT -o %i -p udp --dport 53 -j ACCEPT && iptables -A OUTPUT ! -o %i -p udp --dport 53 -j DROP
PreDown = iptables -D OUTPUT -o %i -p udp --dport 53 -j ACCEPT && iptables -D OUTPUT ! -o %i -p udp --dport 53 -j DROP
This only activates the rules while the VPN interface is on.

That’s stupid.

You have a computer with your name on it in a country where what you’re doing is legal and you’re connecting to it using a process that authenticates with a shared secret from another computer that most likely has your name on it in a country where what you’re doing is illegal.

You’re not fooling anyone and by creating your own crime tunnel with your name on both ends of it and I’m gonna hesitate to use specific legal language to describe the new, more serious type of crime you are now committing because it’s different all over but there’s almost always a type of wire fraud that covers this because banks all tried to do it when different kinds of electronic transfers popped up.

Just use air like a normal person.

Again, you’re making what reads like an incredibly stupid decision.

You have a computer with your name on it, the vps you set up, in a country where your actions are legal and another with your name on it in a country where you reside and your actions aren’t legal.

You connect to the vps using a protocol that authenticates your identity.

Let me just walk through the steps to prosecute you for piracy or a different crime with much more serious consequences:

Through leaky dns, a tipoff, some transformer or just the usual 24/7 isp traffic analysis someone realizes you’re doing a piracy.

They get logs from the isp and if your bad dns doesn’t give you up immediately then they see the outlier ip of the vps. ISPs always cooperate, often the special relationship between companies that are allowed to operate critical infrastructure and law enforcement is enshrined in law.

Whois points them at the vps company, whose policies may require them to get a warrant or equivalent in order to allow law enforcement into your actual running vps but will absolutely comply with kyc aligned requests and laws.

As an aside, you may think that the vps provider could stand up against the cops for you, but they’re not doing that. No one is keeping their mouth shut for $3/mo unless that’s their literal whole business model. They’ll just find new tenants.

Anyway so now they know it’s you on each end and have an airtight piracy case. If that seems like a lot of work to do through for someone whose downloading SpongeBob, it is! Piracy investigations are often not worthwhile as crimes in and of themselves.

The cops will have a strong incentive to get you on other charges, so when they search your house they’ll be looking not only for the computer with your name on it but for anything that could be misconstrued as illegal or prohibited. Hope you’re clean.

But assuming you don’t have an unregistered firearm and pile of illicit drugs next to your computer they’ll still take the computer in for a snoopin. Assuming again that nothing is found but wholesome episodes of SpongeBob on your computer they will without any doubt find your /etc/WireGuard folder with all the config files. Oh, they go to the vps you rented. Imagine that!

In America the crime of setting up a telecommunications system for the purpose of doing something illegal is prosecuted as wire fraud. It might be called different things in different countries but the basic conditions for the creation of law around those actions were about the same everywhere: big money stealin’ using new telegraph technology. The specific technology may have changed but the law inevitably didn’t, so they’ll pile the wire fraud equivalent charge onto you.

I don’t know your country but piracy is probably a low level crime there compared to wire fraud. So instead of facing a fine or a few months for downloading a soccer game now you’re facing a big monetary penalty and many years in jail for creating a system of wire fraud.

Even the often times not very smart police can figure out how to do this. You can check this out by looking in your own countries cop arrest records and see what they’re jamming people up for when it comes to computer crimes. It’s usually the local equivalent of wire fraud when they can get it because the newer, computer specific laws are harder to convict under or have more lenient penalties proscribed.

So anyway, instead of literally building an illegal crime tunnel which is a much worse crime than piracy, spend the money on air or one of the other piracy vpns. You’ll be saving yourself a lot of headache and protecting yourself much better than you did with a home built system.

I took the time to write this out much more explicitly after being told to fuck off because you’re making an incredibly stupid decision. I don’t want you to feel stupid, but I want you to recognize that you’re pursuing a more difficult path that opens you up to much more serious charges and which you are not even capable of getting up and running at the moment.

Just think on that for a second.

You can’t get your illegal crime tunnel working right and you’re asking for help with it on a public forum.

It’s good to try things for the sake of learning. I would strongly advise against trying to learn by doing illegal things and asking for help in public in the strongest possible terms.

Go get a piracy vpn service instead. It accomplishes your goals and keeps you safer than your home grown would if it were working.

I’m really happy to see Bazzite climbing the chart. It’s by far the best gaming-centric Linux distro.

I’m not sure I will ever understand the appeal of Linux Mint. Not because it’s bad, but because there are better distros for every use-case I can think up, especially gaming.

I remember the days of high quality fansubs by people who were just doing it for free because they loved it.

Those still exist and still give you a better consumer experience than these fucking dogshit streaming services.