My ISP replaced our router and since then I can't properly port forward despite supposedly not being on CGNAT according to them, but when I check the IP addresses they're not the same. UPNP seems to work, at least with Nicotine+ but Tixati doesn't. I still port forwarded 37580 though I can't tell if the connectivity is good because of CGNAT. If I check if the ports are open, they're not. Btw, do I also need to port forward for UDP or just TCP is fine?

The status is unconfirmed:

If I disable UPNP, the status is Listening / OK:

Keep UPNP enabled but try other port numbers (make sure you are not using the same port number with other programs). If you still get that error, then maybe your problem is similar to this one:
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If it's the case, it means your actual router can't assign the same port number for both UDP and TCP. TCP port forwarding is enough if you are using only torrents from private trackers, but public torrents will be affected more, because DHT will not work perfectly if UDP port is not forwarded.  
Thanks to UDP hole punching, you can probably get some incoming UDP connections even without UDP port forwarding, but this technique is less reliable.

To check the TCP port situation, you can visit the following website, and enter the port number used by Tixati:
To check the UDP port, start a popular torrent, then temporarily change Tixati settings to receive only UDP connections (Network > Connections > Incoming Peer connection Protocol). Check the number of received connections from Home tab. If you get less than 100 incoming connections in 30 minutes (just an estimation), it either means the UDP port is not forwarded or your firewall is blocking the connections.