I don't think you could make a better case for not attempting to securely email people than this document --- it's good! It's very well done.
My understanding is that p≡p <<a href="https://pep.software/about/" rel="nofollow">https://pep.software/about/</a>> was designed to automate all the modern best practices of using e-mail with PGP.
Can we just write off this whole endeavour already? 20 years of complication, confusion and opportunity for catastrophe.<p>You are far better off mailing something sensitive. Or if you must be digital, asking the recipients for a disposable age key or similar.