I would be happy if my router supported letsencrypt.

Why would I even bother copying and distributing self-signed certificates if I can just properly get a certificate for my own personal router?

It’s idiotic that people still trust pure HTTP and have no option of switching.

If your router needs configuring before it can access the Internet, then it can’t use certificates that require the internet to generate or validate.

Or if you change ISP and need to change your router internet connection configuration, your router cannot be accessed.

When was the last time you needed to configure your router to access the internet?

I understand if that router is something industrial, but then you can probably figure out how to do that over SSH anyway (which is secure).

I think this is the only practical answer, unfortunately. Everything else might possibly be made to work for a personal project, but definitely isn't an option at scale.

The way plex does it works great at scale.

It requires people to care more about "self hosted" than "PM says this will centralize user access and allow us to collect data and better monetize"

I'm not knocking either model. They both work (technically) but you need to understand your market and what works better for them.