The resolution of your video should not DIRECTLY be an SEO factor, however, if you are looking for embeds or other natural BLs, then some industries actually prefer low/high res to distribute. Pay attention to your non-youtube sharing platform clients as well. Sometimes it is your market, sometimes the message, sometimes the platform. There are also platforms I have found that if you throw up a completely remastered 6k movie no one will care, but throw up even a FB pixel with a "4K UHD" title and everyone an their dog will come to take a look. Sometimes I take a step back and forget about the algos and ask... what would I do if this was a torrent?