On the first video, I believe YouTube did not encode your file as 4K or higher. I believe the maximum viewable is 2K as indicated by @biviel
Does the encoding to 4K take more than 24 hours?
On the 2nd video with the “Vertical Woodsplitter”, I can see the 5K option even at low bandwidth from my house.
On the 2nd video with the 5K options (Vertical Woodsplitter), the bitrate for the 5K file on the YouTube server is only 12Mbps, which is lower than the bitrate for the 4K file.
Is it possible to upload a 2GB video file in 360 to a Facebook Group or Page and share it that way?
Working in 5K
Is there more information on this? Does it mean that PC users need to install the Codec pack below?