For a variety of reasons, I still use email accounts via POP3 on macOS, iPadOS, and iOS, which can only be set up with a little workaround. I had a few synch issues across all devices after the recent OS update and ended up having to reinitialize each account.
But now, my beloved Apple Mail is back to its usual self—99.9% reliable, even with my very large database. I find its database structure much easier to manage compared to, say, the outdated Outlook. Honestly, Outlook is a bit of a sad program, and I’ve had a much harder time setting it up in any meaningful way at work!