1080p to 4k was a big improvement in my opinion. I still have a mix of 1080p and 4k equipment. 4k to 8k is real minor to me because 4k TVs are varying degrees of HDR now. Brightness range per zone/pixel and wider color gamut. 8K someday because someday the only TVs you should be buying for the price will be 4k but content picture quality, 4k with quality HDR brightness, contrast, color gamut - minor difference. Just need high quality sources. When I encode something, I use fairly high bitrate AV1. Another 5-7 years and I expect to be encoding everything new at AV2