Perfect doesn't have to be the enemy of good. Signal is Good, it could be better. There is a architectural weakness. There will be some other messenger that ticks all the boxes in the future, hopefully they will take what signal has done and continue to improve it.

Signal is the easy for adoption because of the phone number as identity, but its weak because of the centralization. Its currently the best option. I don't want to spend effort moving normal people to Briar or Session until its absolutely necessary, or those applications improve the onboarding experience.

https://www.securemessagingapps.com/

SimpleX is the new thing to watch imo. Even protects your metadata while still feeling modern and compfortable

Simplex chat is the only one I was able to popularize and its based in the UK