Hello @violetdragon92,
In my self-hosted bitwarden I also needed (https connection between bitwarden and my reverse proxy). Sadly I don’t remember what was the problem. In my case I use non self-signed certificates, but self-signed certificate should also do the job.
Not sure but I guess in case of browser extensions they could work if you have a Certificate Authority installed in your browser. That way you could use them with your self-hosted bitwarden. Maybe if you install the CA on your phone, might also work with the app.
There is a description how to create a CA in case you need it:
Hope this helps 