For now, I've been using the gmail app for Gmail, Yahoo, & Hotmail. I too have a website but I tend to use Thunderbird on desktop for that.
Samsung email kind of lacks features such as when I mark something as spam, it keeps a local list which has a limit rather than sync that info to the server, and that limit was 200 or so last time I checked. I've really only used that for the email at my
ISP. I don't give that email out to anyone and don't use it for anything other than communication with my ISP. I check it very infrequently usually just to clear out spam that has accumulated.
I'm currently looking into an app called "FairEmail - Open source, privacy oriented email" on Play Store.
I think the biggest issue I've had with IMAP is, some apps don't sync well or properly sometimes. So mail you've filed or deleted sometimes still shows on other devices in the wrong place.
My webhost which I've used since 2003 (Totalchoicehosting.com) comes with unlimited POP3 emails, even on the basic shared hosting plan. So I've mostly used POP3 email for personal use.
I've worked for many places where it was all Exchange Server based, so IMAP. But for corporate security reasons, couldn't use any unvetted app. Had to be approved by IT.
Albeit a pain to use on mobile, there's also always the web version of Outlook if you're really in a bind.