Future problems with 2FA?

I have a complicated home system and have been putting off 2FA because of its complexity, although for security reasons I would love to have it enabled.

Problem 1:

My wife and I share our AppleIDs for mail as well as some for other data that we want to share. Email/Calendar/Contacts/Notes/Etc. are on one AppleID, purchases are on another, all shared. Although we were cautioned that we would have problems, we have had a 99.99% success in this system. We have it finely tuned and it works great. If we went to 2FA will we get into trouble with the notifications not getting to the right person? We each have several Macs and an iPhone each.

Problem 2:

At least before COVID we liked to travel out of the country. Would we have problems getting 2FA requests through via Wi-Fi only, if we didn't have cell coverage? Obviously without Wi-Fi we wouldn't be accessing AppleIDs anyway.

I have a programming/tech support background, and delve into the depths of the OS (at least on macOS), but don't want to get caught by any gotchas. I guess at the moment when we switch we have 2 weeks to opt out, but I'm afraid for the time when that goes away and we HAVE to switch.

Thoughts/comments? Thanks.