I haven’t seen a single call to action to donate to Lemmy other than the static sidebar on desktop. Something like that would be far more helpful than complaining about previous Sync users continuing to donate to Sync. Nothing is being taken from Lemmy, Sync already had a big user base and is bringing many of them over here thanks to the app. Let’s call to action to them to donate to instances instead of complaining.
I’d really advise against forcing all code contributions to be copyrighted to you. It doesn’t send a great message to contributors. It also gets murky if any libraries are used.