If you want decentralized private messaging see https://delta.chat/

Signal is nog steeds centralized. Zodra investeerders opdrogen en ze hun servers sluiten is de app niet meer te gebruiken. Een decentrale app zoals https://delta.chat/ zal veel langer meegaan.

I also highly recommended using a temporary email for signing up for stuff whenever possible.

This is the worst security advice I have ever heard. Now someone doesn’t even need to get your password, just your email and they can just use the temporary email provider to reset your password?