Best MacBook for storing and organizing photos

Any of them will work fine for that, from the entry-level MacBook Air to the tricked-out 16" MacBook Pro. In my opinion (FWIW, I am an avid photographer with a library of 40K images), biggest questions to consider are the amount of storage you need on-board vs. external drive(s), and how much editing you'll be doing and where you'll be doing it.

If budget is a concern (and it usually is) I'd lean toward a lower spec Mac but add a larger SSD and if you'll be editing mainly at home a large external display. For example, you could get an entry-level 13" MacBook Air Core i3 which would be find for photo editing/organizing with 1 TB of internal storage, a 5 TB external drive, and a large 4K display all for about the cost (or less) of a 16" MacBook Pro.

OTOH, if you'll be doing a lot of editing on the go, then a larger laptop display may be a better choice.