I have reproduced these issues using a protonmail ed25519 key - Webcrypt still hangs with my test decryption configuration:
- encrypted message (not signed)
- blank sender field, protonmail ed15519 public key pasted into recipient field
- protonmail ed15519 private key loaded to onlykey using Auto Load
I get the same error as before when trying to use stored keys for OpenGPG with protonmail ed15519 keys too.
I will continue testing using protonmail keys (as far as I can determine, they follow the same format as the same keys generated by gpg, but it’s good to be sure).