NextCloud-Container with NFS-Share

I’m new with NextCloud and have a few questions/problems.
I’m running ProxMox with a TrueNAS-VM and ReverseProxy-LXC.
I want to have NextCloud running in its own LXC (debian) while using 3 NFS-Shares from TrueNAS as its data folders (Movies, Private,…).
Installing NextCloud normally without NFS works pretty fine, after I install it, I open the website with the config site. Sadly, there, it is only possible to use one folder.
I tried using /home/nextcloud as the data folder and then mount NFS to three Folders inside the data folder. They don’t show in the WebUI but NextCloud knows they exist because I can’t create folders with the same names (obviously).
I know there should be better ways and solutions for it, but I didn’t find anything helpfull.
Thanks for your help.

You could try mounting them in External Storage app.

@just Thanks for your reply.
I think it’s worth a try. But I want to prevent the possibility to write on the local storage, because there should be no data. Is there a way to block/prevent this?

You can mount read-only as far as I remember.