Dimensions for 4k animation

Hi there, I have a ton of 4k animation clips but yet to post because I feel unsure of proper dimensions. Can someone advise as to the best 4k dimensions to use for my uploads? 3840x2160 versus 4096x2160? I know some are used for some things, and others are used for other things, but I feel like I need to just commit to one of them. Any recs on what would be best as a general rule? My stuff is geared towards corporate video, university, general television advertising. Thanks!