Firefox

You definitely can't trust KeePass.

I used to use them but they had a pretty bad exploit for a long time and there's no telling how many master passwords were stolen.

https://www.malwarebytes.com/blog/news/2023/05/keepass-vulnerability-allows-attackers-to-access-the-master-password

I'm not aware of bitwarden having any exploits.

They hold some of the hardest to aquire security certifications in the industry, both server and client are open source, and they regularly undergo and post the results of external third party audits.

Out of all password managers they are by far the most trustworthy

You can always self host or audit the code yourself.