So I'm wanting to put 28/R10/14 tires on my 2016 590i. I'm intending on buying John Deere OEM 14" rear rims for the tires. I'm curious who has made this transition and were there any regrets? Any problems with this mod? Thanks for your help.

Something like the:
Maxxis Carnivore ML1 Tire 28/R10/14 https://www.chapmoto.com/maxxis-carn...yABEgKJtvD_BwE
BF Goodrich https://www.4wheelparts.com/p/bf-goo...a-681485879429

If you want to keep some of the cost down, consider a 4 lug trailer wheel and suitable rubber on top. You can get nice rims and much better tires which will last longer. Also, the OEM rear rims might be too wide for the front as the extra width can grind into the well. See how much clearance you have with your stock front. Also the offset of the rear rims are very different from the front rims. Remember you need clearance when your suspension compresses too. If you want a general idea, look up "street tires" and you'll see the 15" rims I used. I believe your rims would be smaller with the 4 lugs but you can configure them pretty much any way you want.

Forgot to add. ATV tires run around 18-24psi. Truck, trailer, or automotive tires run 32-35psi typically. Makes a big difference on load, flex, ride, etc.