Confusion around seafhttp and external nginx

I just migrated from a non-docker v12 to a docker v12 and after a few problems i managed to get it running somewhat. My last issue is that my desktop seafile client is stuck in “waiting for synchronization” and the logs show
[03/04/25 18:21:18] Bad response code for GET https://<myurl>.com/seafhttp/protocol-version: 502.

There are no docs around seafhttp for docker based setups with external nginx.

The auto-generated nginx.conf gave me a clue that seafhttp is running on docker port 8082 so i forwarded that in the seafile-server.yml file and used the code for /seafhttp from the generated nginx.conf but it is not working.

Is there maybe a config i have to remove? Like the go-fileserver or something?

I think i found the problem in my seafile.conf:

[fileserver]
port = 8083

That port is 8082 when generating fresh configs. After changing it i no longer have the seafhttp error but i did saw one line of
Bad response code for POST https://seafile.diezuras.de/seafhttp/repo/head-commits-multi/: 502

Still the desktop client seems to be working (Download and Upload)

I also did this without exposing the 8082 port and with no /seafhttp location in my external nginx.