I agree, but it's impossible to convince my less tech savy roommates and friends to let me install a root certificate. "That sounds like i could read all their private messages", lol. Just let me have my certificate for https in my local net. I don't need to be "even more" secure. I get that that's necessary for public services, but surely not for local selfhosting. I don't even have a port open other than wireguard. And i would not even care "if a roommate hacks/gets access to a guests voice commands for home assistant." (Not complaining at you but at this trend. I do think my use case is valid)
You are gonna laugh if i tell you how i partly automated this workaround. A script changes the (dyn) dns entries of all subdomains to point to my public server in a datacenter. There, it ssh's in and requests the certificates with certbot. Then, it restores the dns entries and downloads and installs the certificates in the local net. Still requires manual supervision and sometimes intervention. My domains do not support automated dnssec. I don't have time to secure my local net enough to feel good about opening ports. If all certificate lifetimes get shorter, i'll either have to switch my domain provider or give up selfhosting for other people.
I did that for myself a few years back. But i can't convince my roommates, let's not even speak of guests, to install a (my) root certificate. My android phone still complains about "possibly supervised network traffic" since back when i installed my root ca. Maybe there is another solution im not aware of, but i can't think of any