I have used nextcloud-client on other distros without issue with KDE so im not sure what the issue is. I am running secureblue nvidia pre turing, and when I open nextcloud desktop it just closes immediately. When I run nextcloud-client via the cli I get this:
nextcloud
QWaylandGLContext: Failed to create the decorations EGLContext. Decorations will not be drawn.
[3669:3669:0217/122635.652229:FATAL:credentials.cc(136)] Check failed: . : Permission denied (13)
Trace/breakpoint trap (core dumped) nextcloud
I installed nextcloud via rpm-ostree as it wasn't available via bazaar