Looks promising. Thank you!

Thank you very much! I will have a look at those.

well I would pretty much configure everything and my friends would simply „use“ the servers by connecting to it via the games (Minecraft, Arma etc)

Have you tried using ZeroTier? I don‘t have much experience using Tailscale but have been using ZeroTier for two years now without any problems. Runs great on Synology

I use a selfhosted public DNS which runs AdGuard Home where I have multiple block lists running that filter my whole Internet Access from Home, which not only makes my internet at home a lot faster because Ads and other annoying or malicious sites don‘t even get loaded/sent to my home network, but makes it also safer. I run it on a VPS since I have my parents and friends use it too.