Discord has always had dark patterns which basically ban anonymity. If you aren't fingerprintable enough (using VPN, etc) they will force you to enter a phone number. They also encourage guild admins to require it, although it is technically a choice.
I've been blocked from joining the discord of some games I play because I refuse to enter a phone number.
I have used Discord for a number of years always via VPN and I've never given away my phone number.
Yeah any level of "anonymity" on Discord died long ago, if it ever existed in the first place. For me, any platform which doesn't enforce Tor is considered very NOT anonymous - even if its accessible through Tor, I don't trust it that much if I'm one of the only people actually using Tor to access the platform.
SimpleX seems trustworthy enough, with thoughtful design decisions, even if it fails my "forced tor" requirement. I haven't spent the time to dive into Session's architecture, but it's on my to-do list, currently the marketing copy makes it look like the best choice.
Phone text checks only stop people who don't know they can be easily bypassed anonymously