Short lived certificates force sysadmins to automate the renewal process. This prevents expired certificates due to forgetting the manual renewal.

That was already the case with the 90 day ones. No sane person is going to be manually renewing certificates every 3 months.

Didn’t EU pass a regulation regarding that? If I recall correctly all portable devices sold in the EU after February will will need to have a user replaceable battery.

There is Headscale if you don’t want to use Tailscale servers.