The below article is worth a read, and similar to other posts here, the author thinks that due to all the data breaches it may be possible that our accounts are being hit by hackers trying to brute-force the password, causing Apple to lock our accounts. He proposes that you change your Apple ID email address. In the case of some users, you could actually use a + character, meaning your current (soon to be old) email address is no longer a valid Apple ID. If your old address was 'user@gmail.com' it could now be something like 'user+sometag@gmail.com'. Email from Apple will still deliver to your existing 'user@gmail.com' email inbox, but your Apple ID would be considered as 'NEW'.
Link: https://gloutnikov.com/post/2020/prevent-appleid-from-constantly-getting-locked/
And in addition, here is some useful reading on enabling 2FA from Apple, in the event that you are "forced" to go this route.
Link: Two-factor authentication for Apple ID - Apple Support
Looks like you can make it work with only one Apple device and any phone, if you can receive the SMS that is.