Honestly think burn-in is a thing of the past. Only worry would be if you maybe watch a lot of news or other programs with a static banner - for literally hours a day, every day - for years.
8k is a gimmick because there is no 8k content out. I would honestly not spend extra money on 8k anything (maybe in 10 years from now though)
As much as I love OLED, I would say first evaluate your room. If there is a lot of bright, natural light, windows etc, get the samsung Qled I mentioned above ^ which is their top 4k model
Samsung has a discount program if you meet the requirements
https://www.samsung.com/us/shop/discount-program/