Were you using simplelogin.io, which is part of Proton? It is actually possible to reply or send mails from the aliases you create there. The feature is called reverse-alias.
I tried that, but I much prefer the haptics of real paper and writing with an actual pen. Also, I really like the look of ink on paper. Of course, there are still cases when a tablet is just the best. For example, when annotating PDFs.
Were you using simplelogin.io, which is part of Proton? It is actually possible to reply or send mails from the aliases you create there. The feature is called reverse-alias.