This is something I have investigated personally as I couldn’t seem to get BW to connect to my node over TailScale after having a bad time with Tor (Thanks iOS!)
After some digging I discovered that Tailscale recently changed the MagicDNS Tailnet format from beta.tailscale.net to ts.net - Bluewallet does not allow http clearnet connections without being whitelisted first.
I have since issued a PR to Bluewallet to include ts.net in the list of exceptions for their android & iOS apps respectively, which has recently been merged - so once they rollout the next set of updates this should work. 