Ive got really cheap lg 49 uh620v tv 4k hdr everything looks great even though its not a big leap from 21:9 2560x1080 in terms of ppi, thats Just my opinion
WATCH OUT FOR CHEAP 4K!
Theyve got RGBW panels which means every 4th dot is no rgb but white, which makes it more like 2880 than 3860 whatever, if you want truly enjoy 4k go big or go home, dont fool yourself like i did