You are running the VMs headless right?
An AWS S3 bucket to sync important files off site. £1 a month.
Pi-Hole, Nextcloud, local storage and email are used constantly. All bring great improvements.
Ansible and Zabbix provide ‘support’ for these applications.
Media streaming is a ‘nice to have’ but not essential. Wireguard is seldom used but still very important.
The laziest way to fix your issue is to chmod the shared directory to 777.
I would only suggest this if this is on a LAN and you are the only person using the different machines.