So while also implementing Tailnet locks and other security measures to constrict traffic flow, I'd also consider going a step further by only permitting server or resource access based on client certificate validation (in other words, a client that's missing a trusted certificate is rejected from even attempting to initiate AuthN); that way even if your Tailscale network is compromised somehow, untrusted clients and endpoints can't make inroads into your infrastructure as easily.
Is that a gigantic PITA to implement? Oh heck, you betcha it is, and I doubt 99% of folks need to go that far with their homelabs or home services. Still, that'd be my approach to zero trust - trusting Tailscale only so far as enabling virtual networking, but not blindly trusting traffic coming over that network at any point.