Another option is to make the youtube video private. Then you have the option to only share it with specific people. If it’s unlisted, then anyone with the link can view it.
Hosting on a VPS will get expensive. 4K video takes up a lot of space. If you want adjustable quality, then you will need to store multiple copies of the video at various resolutions and bitrates. A cheap VPS won’t have a GPU to do real time transcoding.