This is why decentralization is the future. Any sufficiently popular walled garden will have such problem (I'm looking at you Signal). Consider using Matrix instead.
I like Matrix, but when it comes to ease of use and onboarding Signal is easier for the general audience.
It might be easier, so what? Apple's products are supposedly more privacy-oriented than the Facebook's/Google's. So what? The idea is that we should be rooting/encouraging others to put decentralization and freedom as a top-priority choice, not to keep excusing ourselves into adopting solutions that are bound to become another dominant walled garden.
If you want to argue for Matrix vs XMPP, or XMPP vs SIP or any other decentralized protocol, by all means go ahead. Just please don't come with "I like Matrix, but here is a completely lazy cop-out that I will use to justify to not fight the good fight"