Good question. You could set a domain name point to your IP in your router. That has different names, might be hosts-file or just buried somewhere in the DNS settings of the router. Or machinename.local or .lan works. That should give you some internal domain name, valid inside of your network / wifi.
Getting proper certificates without exposing anything is tricky. If that’s really needed: You’d either generate a self-signed certificate manually and import that onto your devices. Or you need to do some trickery with letsencrypt’s DNS challenge. That’s not super easy, but possible: https://m.youtube.com/watch?v=qlcVx-k-02E
I don’t use Bitwarden. There might be another specific solution to do it.
It won’t go. At least not in the near future. They’re just growing. And that comes with consequences. The article says they’re at it. And doing a good job.