>certbot
I'm not surprised the flagship certbot automagically handled the deprecation since you apparently consistently update it. But many setups, especially those without auto-updates and other moving parts, just stopped working. And certbot would've too if you hadn't have made sure it was up to date. And some acme clients never supported 2 and just died. It will happen again.
>a centralized dependency with an inconvenient workaround.
Except there's no workaround with QUIC based HTTP/3 because all the libs people use come without the flags to allow self signed certs. So 99% of browsers/HTTP using software released is stuck with CA TLS or no communication at all.
It doesn't matter if you set up a custom CA for internal use or if you enable it in your custom http/3 lib build of your custom build of $browser. People still won't be able to visit your hosted HTTP/3 site with your custom CA. Not without you installing your root cert in the browser or system cert store of most people on Earth. That seems unlikely to happen.