Some of my friend groups have moved to Signal, it's ok in a "good enough" sort of way but it's not a perfect replacement.
I'll have a hard time persuading family groups to move though, WhatsApp and Facebook are cultural touchstones for them they won't see any point in moving
You only need to persuade one popular person in the group and have them suggest it and everyone will follow. Although I don't know of a viable alternative to Facebook, going from WhatsApp to Telegram or Signal, like you said, is "good enough".
I'll have a hard time persuading family groups to move though, WhatsApp and Facebook are cultural touchstones for them they won't see any point in moving