will Thunderbolt 3 docks work with my MacBook Pro (Retina, 15-inch, Mid 2014)

Actually, wife just informed me she is tired of my constant complaints as to how slow my 2013 iMac is in dealing with everything, but especially Photos app! She gave her blessing to replacing the iMac! Thus no need for jury rigging something with my MacBook Pro!

john b;

Actually, after spending a lot of hours reading online reviews, I'm seriously considering waiting til the anticipated M1 chipped 24" iMacs come out in mid2021. The reviews of M1 Mac Mini are great, but I'm sorta hooked on the iMacs rather than putting a system together with Mini. So.... my question is just to confirm that I read your info correctly. The TB3 to TB2 adapter cable would be to connect my MacBook Pro (Retina, 15-inch, Mid 2014) to a TB3 dock? And then I could continue to use the TB to TB cable I'm already using that allows me to use my older iMac as second screen for the Macbook Pro, bypassing the dock for hooking up to the older iMac as a second screen? (My current problem is that my 27" Late 2013 iMac just can't handle the Photos library with 37,000 family photos. And yes I used to take 20 shots at a time in order to get one good shot of the kids in each situation, and just dump them all on iMac for later selecting and culling. I seriously regret that now, as I am spending hours a day to delete 100's of photos an hour. But the old iMac just isn't up to the task. So I'm thinking of using Macbook Pro, with the photos library (like I've already done with the Music (iTunes) library) , on an external hard drive. I use Carbon Copy Cloner to make backups of the external drives.

Any specific recommendations you have as to a specific brand or model of dock would be appreciated. It needs to be compatible with either powered USB A hubs or have sufficient USB A ports to hook up to at least 4 older external hard drives (or I might have to upgrade to newer external hard drives.

Thanks