OpenKeyChain provides you with the ability to encrypt stuff in your device using OpenPGP. You can get it from f-droid.
Once you setup a key, you can use it to encrypt anything. For example you can encrypt your email directly by using a supported client, like K-9 or FairEmail.
To encrypt your passwords, you can use Password Store, which is a simple yet effective password manager for Android. Here's the GitHub, and f-droid links.
It works really well. No need to depend on any 3rd party for keeping your passwords safe.