I feel so seen
I'd seriously be willing to pay in a crowdfunding campaign for an indie dev to develop an GNOME Evolution (npub184x…2a9r) GUI feature (whether in Core or as a plug-in shipped with the app) to schedule-send emails with #IMAP + #SMTP (& eventually #JMAP).
I added my usecases examples in this ticket's description: https://gitlab.gnome.org/GNOME/evolution/-/issues/411
Know additional ones? Let me know here.