Encryption with Contact Form 7 does not to work

[zrknlzr]

Wordpress Version: 5.9.3
Plugin Version: 0.8.0
PHP: 7.4

Configuration:

• Created fresh keypair on client computer and added the pubkey in the "Admin Email PGP Public Key" and to the admin user profile.
• Created signing keypair in plugin settings
• Basic Contact Form 7 form is set up to send everything to the site admin.

Expected results:

• Admin E-Mail should receive a signed and encrypted E-Mail

Actual results:

• E-Mail arrives only signed but not encrypted

Research:

• Here another user in comments at the bottom claims it didn't work for them either in 2019 (no further details though)
• The plugin version on wordpress.org seems to be still on main branch from May 2021 and i personally can't tell if the develop has changed anything to address this issue but i will try to do some more testing.