

Can you use a dummy address or a friend’s address in another country and/or sign up via a VPN to mask your location? There are companies that will open and scan your mail and make it available online so it could be a real address. But they are a little pricey. It’s likely due to UK laws not the provider themselves, so probably all reputable providers (that follow the law) may require it.
I use Signal because it’s the best balance of privacy and security vs. convenience and reliability I have found. Not self-hosted, but I’ve yet to find a self hosted alternative that is as reliable, especially since I don’t want to set up distributed servers, and it’s one of those things that “just needs to work” or people will abandon it quickly.
And the older people I’ve convinced to use it, like my mom, have had very little trouble adopting it. It helped that RCS messaging is so unreliable on my phone since Google or my carrier keep seeming to break it (likely became I use GrapheneOS), and also for those with iPhones it is way more compatible with itself vs Apple and Google refusing to implement RCS in a way that all features work between them, like message reactions. Without RCS, my mom couldn’t send me decent quality pictures of my niece all the time, and I couldn’t send nice pictures of my outfits to the girl I’m dating, LOL.