If I don’t remember wrong Android will always use your DNS config over the WG provided one so make sure to leave it blank. As for the routing I have a alternative solution that could maybe work using this app in combination with the WG tunnel. But when it comes to your current setup I suggest you try the following.

1. Make sure that the IP and port of your DNS are accessible from your Phone you can use Termux if you want to ping and do a nc to do this.
2. Make sure that the network that your WG connects to has its default DNS setup to be your unbound.
3. Consider getting a Router that can run OpenWRT and then learn about vlans to create two networks(also 2 wifis) one for your roomates and one for you. Also you could setup WG on the OpenWRT router itself!

If you really want to solve this problem you might want to read up on routing and networking in general! I suggest you start with Wikipedia! That’s atleast where I started! :D

I wish you good luck on you self hosting experience!

As far as i have understood it was a bug that caused confusion on what direction Bitwarden was going, but for now everything seems to be going well! But as always keep a eye open!