Just checked, it's working fine for me Seadroid: 3.0.0 (from fdroid) Server: 11.0.8 Pixel 8 android
It was working for me before as well with the 2.3.x version that I was using (don't know the exact version)
For example, in my aegis, I can select backup folders then in the file browser, seafile shows up and lets me select a folder for backup as expected.
You could try restarting the phone in case it's a weird android issue. Then you could try 3.0.0 seadroid.
What happens when you select the 3 line button on the top left? For it shows seadrive.