Hi,
After we just tried out BigBlueButton for the meeting, I have to say that I found its mobile support unfortunately lacking. It doesn't have an official Android app as far as I can tell, and the only unofficial one I found (https://play.google.com/store/apps/details?id=com.bigbluebuttonmobile) says "this item isn't available in your country" when I try to install it in the US. I can open the website from a mobile browser but then it doesn't have any mobile-specific UI or features (like using the "phone call" speaker instead of the big one), so it's pretty useless for that.
I usually need to take part of the meeting on the go, and it seems that the only useable option for that is the POTS phone bridge which is obviously not a great experience (can't raise hands, can't see when other people have hands raised, etc.). I'm not sure for what reasons other people were asking to switch away from Google Meet, but I just wanted to add the data point that at least for my use case, it worked way better.