Mount nfs at startup as specific user, and allow unmount?

I am using:

$ lsb_release -aNo LSB modules are available.Distributor ID: UbuntuDescription:    Ubuntu 20.04.2 LTSRelease:    20.04Codename:   focal$ mate-about --versionMATE Desktop Environment 1.24.0

... as an NFS client.

I have an nfs4 share on the server; my entry in /etc/fstab on the client is like this:

172.16.0.5:/mydata /media/user/mydata_nfs nfs4 nosuid,nodev,nofail,x-gvfs-show,rw,relatime,user,noauto,uhelper=udisks2 0 0

I have manually created the /media/user/mydata_nfs, which at start has these permissions:

$ ls -la /media/user/total 20drwxr-x---+ 5 root          root          4096 Jul 25 15:56 .drwxr-xr-x  3 root          root          4096 Jul 19 18:43 .....drwxr-xr-x  2 user          user          4096 Jul 25 12:11 mydata_nfs

The above fstab entry allows that the share is not mounted at startup, and so I manually have to click in the "file explorer" GUI (here caja), to do so; however, once the share is mounted, the ownership (and timestamp) changes:

$ ls -la /media/user/total 20drwxr-x---+ 5 root          root          4096 Jul 25 15:56 .drwxr-xr-x  3 root          root          4096 Jul 19 18:43 .....drwxrwxrwx  6 root          root          4096 Jul 29 06:15 mydata_nfs

On the NFS server, no_root_squash is enabled; as I understand it, in that case UID/GID from client user is propagated to server, and since on server I also have user with uid:gid of 1000:1000 (as on client), this works fine for me (when I create files, etc, inside the share from the command line on client, ownership of user is kept on the share) - except for the mount point on client being owned by root (which causes me problems: some programs installed by snap will not even list the share as a directory).

Also - even with the above fstab line (which requires me to mount manually), when I try to unmount from the GUI, I cannot, and I get a dialog with:

Unable to unmount mydata_nfsError finding object for block device 0:56

So, what I'd like to have is:

• NFS share to be automatically mounted at startup - with user owning the share
• Allow for user to unmount the share from the GUI

Is this possible at all - and what would be the right fstab line to have that?

Note that uid fstab option (which otherwise does this kind of mapping for ntfs) does not work here - syslog will complain:

Jul 29 07:03:49 mypc mount[1148]: mount.nfs4: an incorrect mount option was specifiedJul 29 07:03:49 mypc kernel: [   17.179641] nfs4: Unknown parameter 'uid'Jul 29 07:03:49 mypc systemd[1]: media-user-mydata_nfs.mount: Mount process exited, code=exited, status=32/n/aJul 29 07:03:49 mypc systemd[1]: media-user-mydata_nfs.mount: Failed with result 'exit-code'.Jul 29 07:03:49 mypc systemd[1]: Failed to mount /media/user/mydata_nfs.

Also allow_other is unknown parameter for NFS.