Get a VPN with port forwarding. Problem solved.

In qBittorrent what is the Status of DHT, PeX, LSD when you click on the torrent and click its Trackers tab?

I’m on CGNAT

Your own torrent peer is not and cannot be connectable (port forwarded), unfortunately.

Not sure if you'll be able to get much improvement, it'll always be slow or impossible depending on the amount of connectable peers in the torrent swarm. But you should be seeing okay-ish speeds if the torrent you're trying to download has tons of connectable peers. Does the torrent you're downloading have a lot of seeds/leeches on it?

PS - If you're saying everything usually works fine then something changed, could try restarting your internet router just to rule that out.

Okay, now that's weird. I switched to "any interface" for what to bind to instead of my Ethernet interface and that somehow made torrenting work again?

Sounds like ISP throttling. Are you using a vpn?