Do you need to access the rest of your network? If you're just using that machine as the file server and gaming server, just run Tailscale on it, that way only that machine is accessible.
That being said, as long as your server is locked down to only allow connections from outside via your Tailscale network, then you shoukd be pretty safe. Your point of failure becomes the security of that netbook, if it becomes compromised, the attacker has access to anything on your Tailnet too.
Make sure you implement 2FA for your tailnet, and practice good security for your netbook if you go that route.