That's... the situation as described in the post which the comment above you was responding to?

> The only downside is that internet connectivity being down means, e.g., you need to remember to load the grocery list before leaving the house that has the server in it

Wireguard or Tailscale Inc. are not magically going to resolve that situation. Does Tailscale even work locally if your internet is down or does it require their cloud for NAT punching regardless of whether you're on the server's LAN? For starters