When using Gnome, it is quite convenient to mount remote locations directly in Nautilus. As an example, I often mount my Google Drive work folder, also my personal NextCloud instance.
While this makes it easy to work with remote accessible files from within Gnome tools, it is less obvious how to access for example files from within a shell like gnome-terminal.
Nautilus uses FUSE to mount remote locations. You can find more in the Gnome documentation GVfs.
With this knowledge, the solution is this directory:
In that directory you will find the actual fuse mounts of the remote locations linked from within Nautilus:
$ ls -1 $XDG_RUNTIME_DIR/gvfs 'dav:host=nc.bayz.de,ssl=true,prefix=%2Fremote.php%2Fwebdav' 'google-drive:host=redhat.com,user=ABCDEF'
Those are directories, so you can just work with them as with usual directories and change into them, edit files, etc. Of course, depending on the internet connection and the endpoint and the protocol the interactions will not be comparable to working on files on your local SSD. But it might be just enough for your use cases.
Thanks to strugee for this detailed comment on StackExchange.