simplex is good as an alternative

IIRC it’s not open source

i use simplex with people i used sms with before, and matrix for everything else

it would be nice, especially for users like me, who only use lemmy on mobile

(also see the issue on github)

Get a password manager.

how was this generated?

this is not related to the matrix.org matrix, according to this article: https://www.bleepingcomputer.com/news/security/police-seize-matrix-encrypted-chat-service-after-spying-on-criminals/