oblique torrent
You might need to insert (-I) rather than append (-A) your nat PREROUTING rules since Docker itself also creates nat PREROUTING rules.
Also using a capture tool such as tcpdump or tshark can help narrow down the issue.
You might also need to enable forwarding but I kind of doubt that's necessary
vast flint
just use the provided guide in pinnged msgs for wireguard in #linux-help
oblique torrent
Depends on what the issue is. I suggested a few things for you to try already. It's probably best to do as Jolty suggests anyways though.