I use Nextcloud, but as you said it’s a bit big, and with each update it’s slowly turning into more of the entire G-Suite.

I’ve used filebrowser, but be aware that until just a few days ago, it gave out access to a shell. Even with that turned off, I’d be very weary of allowing access from out of the VPN. I had a server pwned with filebrowser appearing to be the vector, and to my memory console access was disabled for the account most likely breached.