Nice. Yeah nowadays I get something on 4K UHD Blu-Ray if it's in 4K, and if not, I get it in Blu-Ray if I can.
The only case in which I'll get something on iTunes is if iTunes has it in HD and there's no Blu-Ray release yet (like 9-1-1), or there's no physical release at all (like The Carmichael Show). The vast majority of what I buy is still physical media.
I use Amazon prime to buy movies. Mostly because I have a fire stick and it is convenient. Also, I like having all need digital stuff in one places.
Lastly, I think prime uses the movies anywhere features when allowed by the distributor, which means I should be able to watch them with other services.