Any system beyond a vanilla install will need some tweaks to fit your use case(s). And these tweaks often end up as a stack of glass boxes over time, unless meticulously planned purpose built from the beginning.

As long as it’s manageable and secure, don’t let “perfect” be the enemy of “operational”.

Wanting to rebuild from scratch is pretty common. The question is whether you need to and should. You have to weigh cost and work hours up against any benefits to figure out the answer.

No, just one. You set up one device/server as a VPN gateway (often called VPN concentrator), and you will have access to anything the concentrator has access to on your home network.

Either you just your VPN concentrator as your jump box, or you set up routing and firewalls to be able to access them directly.

I have no experience with OMV specifically, but generally making things accessible from outside your house means exposing it ti the internet.

However, what you can do is to only expose an openvpn port, so that to gain access as if you were at home you could connect via o0envpn first.

rsync if it’s a from/to I don’t need very often

More common transfer locations are done via NFS

DO NOT call the police. They will confiscate the server as evidence, and lacking any other suspect, you will be their primary lead. Police aren’t about convictions or justice, they want to consider a case solved.

By law, you are not liable. But because of law enforcement incentives, it will absolutely become your problem.

Mandrake was the 2nd distro I tried some 25 years ago.

I’m hearing good things about Framework, provided you get the hinge upgrade.

If you need something beefier, personally I’m using a Lenovo Legion 7 (2024 version… that white one, bought it a few months ago), and I’m loving it. Linux Mint worked out of the box, but I chose to replace the stock wifi driver with a better one.