I suggest adding mailo dot Com
imap smtp are enabled by default
Plus their webmail app facilitates creation and use of sign/encrypt keys (which I have not tested for interoperability)
AFAIC recall the attachment limit is around 15m. It is much better suited than il kcoc (NSFW suggestive images & phrases) spelled backward.
It does offer totp 2fa, and per app passwords. Not me-tested.
It has calendar and Web disk. I haven’t sorted out a stable CalDAV solution with gapps uninstalled.
Ports 993 465. I don’t recall if 500 range imap.port is an option.
Offers 5 aliases. Wink to aliases feature request here.
Requires adblocking with webmail. I recommend uBlock origin & nextDNS.