Since I self-host e-mail anyway, I switched to a well-greased Roundcube web UI for desktop and FairEmail on the phone. Searching through 20 GB of mail, including text in PDF and Office formats, is more or less "Google-instant" thanks to dovecot-fts-xapian. Having everything in Maildirs for me is very pleasant.
For calendaring I now use Radicale and either Infcloud web UI on desktop or CalDAV-Sync on phone. Could be tighter integrated with e-mail but the old Unix ways of one tool for one job have merits, like all calendar entries are now file system objects and under Git control. Impossible now to fat-finger half the calender and having to jump through hoops to restore entries.