ThatPlayer parent
I just tried it on a 2nd phone and it seems to work.
I got logged out of Signal after setting up Molly
Now reading this on the GitHub page:
"If you wish to use the same phone number for both Molly and Signal, you must register Molly as a linked device. Registering the same number independently on both apps will result in only the most recently registered app staying active, while the other will go offline."