More specifically, if I was to attach my public key to every email — even when the recipient doesn’t use PGP.

My assumption is that “life would carry on” and there would be basically no difference but I’m not entirely sure.

the process of using PGP for encrypting content (text messages for example) is something I’m only just started understanding after some reading and practicing

EDIT

Since a couple of people have mentioned it, my email provider provides E2EE between users but it I want to have E2EE with non-users and via my aliases (SimpleLogin) with custom domains I’ll need PGP