> Unfortunately, just reading the FAQ a few red flags. It doesn’t allow importing encrypted keys. This is an automatic “nope” for me.

This is answered in the FAQ:

Can I re-use my existing private key?

Yes. The best way is to send an Autocrypt Setup Message from the other e-mail client. Look for something like Start Autocrypt Setup Transfer in the settings of the other client and follow the instructions shown there.

Alternatively, you can import the key manually in “Advanced settings / Manage private keys”. Caution: Make sure the key is not protected by a password, or remove the password beforehand.

If you don’t have a key or don’t even know you would need one - don’t worry: Delta Chat generates one as needed, you don’t have to hit a button for it.