I just want to add that Signal is not associated with Facebook. WhatsApp is, but uses the Signal protocol. The creator of Signal actually worked with them to make sure they implemented it correctly. I totally get the aversion from anything Facebook related, but Signal itself, isn’t.

The login issues seems to have been fixed with the recent update.

https://join-lemmy.org/news/2023-07-11_-_Lemmy_Release_v0.18.2

Have your tried clearing your cookies/cache for your browser and logging in? For your mobile app, remove your account from the app or clear the cache in the app settings.

Signal doesn’t store your contacts or messages; it’s end to end encryption. What are you suggesting they’ll “sell out” if offered enough money?