Apple couldn't care less about what type email methods you use. They don't even care if you don't use the
Mail app. Nor are they trying to "railroad" you into any particular method, ancient/modern, English/Greek. They make no money on your using iCloud and certainly none on any of the other organizations.
Mail has offered that list for a very long time: iCloud/MS Exchange/Google/yahoo!/Aol (that should give you and idea how long that pref list has been around!
). It is simply a way to allow the OS to help you set up most of the things those different (sometimes hybrid) services need. You don't have to use any of them unless you want to use Mail to send/receive mail with that 'company'. Please notice that there is one more choice: "Other Mail Account...". Note also that there is an ellipsis there. Use that choice for any service not already named, but be aware that you will have to enter all the details yourself.
As for "what to do" to use IMAP, there is only one step. Create the account in
Mail and then open Mail whenever you want to read or send an email. You absolutely positively won't be able to tell whether the email came via POP or IMAP, they will all look exactly alike.
Please try to ask about only one problem in any post you start. This one is about your being requested to enter your Apple ID password. That is used by many of Apple's app, not just
Mail. I'm not sure what POP vs IMAP or 2FA has to do with the threads topic.
I hope you are following the advice that is offered so often here and other help sites: Get and Use a good password manager.
BTW, your Apple ID and password don't expire. It fact, it's nearly impossible to even change them! They seem to be engraved in Granite somewhere in the underground caverns of some mountain! Probably in a cave dug by a "Snow Leopard" or in the "High Sierras" or maybe on "Catalina" Island.