iMac 21.5” (Retina 4K) vs iMac 21.5”

Which iMac 21.5” should I buy? Retina 4K with i7 processor or the basic one with i5 processor? I am a basic user-uses the computer mainly for emails, surfing websites & word document for work. I am still surviving well on my Macbook Air 11” i5 processor with 4GB 1600MHz DDR3 memory. I also plan to buy a new & latest Macbook laptop end of 2021 for further studies. Do I even need the latest Retina 4K or is it more worth it to pay abit extra than getting the basic model? Thank you! Appreciate any wisdom for a simple user like me :)