I'm glad you were able to move all of your contacts to Signal! That hasn't worked for me, though many people have joined me on Discord. My siblings are sort of straddling between Messenger and Discord, just like me, but they tend to be more responsive on Messenger. Perhaps they only use Discord to appease me.

I've never enjoyed the chat heads and always disabled them right away. I don't notice ads in Messenger, though I mostly use it from a desktop browser with uBlock Origin enabled!

But as a I said, I only use Messenger because I have to, as it is the primary messaging service family members tend to stick to.