Erik Moeller is a user on social.coop. You can follow them or interact with them if you have an account anywhere in the fediverse.
Got my (non-NFC) #YubiKey holding GPG subkeys working with Android and K-9 mail client. First time in my life that I've used PGP encrypted mail on a smartphone. The phone part turned out surprisingly easy -- OpenKeychain is great!
Next up: trying NitroKeys (a bit more open than YubiKey, + a proper USB plug which is more convenient for GPG use).
@eloquence You can even use the password manager Password Store [1] with OpenKeychain.
[1] https://f-droid.org/en/packages/com.zeapo.pwdstore/