it's a challenge for sure, however, I've managed to get my extended family all on Signal which is about as much reach as I could hope/expect to achieve.

That's my household, my parents, my grandparents, my parents-in-law, my sibling(s), cousins, aunts/uncles, sibling(s)-in-law, friends, and my colleagues.

Some of my children's' friends' parents who I'm friendly enough with also began using Signal so we can communicate. Those who are school friends but not outside-of-school-friends, we can communicate with via the school's app.

Almost anyone I could want to communicate with is on Signal, all of the family is directly or indirectly because of me, and friends and colleagues has been a combination.

Anyone I don't know well enough to have a conversation about privacy and Meta being the antithesis of it, is not likely someone I need to communicate with.

All in, my wife, on WhatsApp, isn't really "keep[ing] me in the loop", unless we're messaging a trades-person or similar, but that's infrequent enough to not be an issue.