8K equirectangular assistance

[SorryAboutYourCats]

I'm trying to create an 8K stereoscopic 3D equirectangular fractal to view on YouTube [360° view for VR HMDs].
However, there are a few roadblocks that I'm trying to go around and would love some assistance if possible.

Resolution limitation with h264 / .mp4:
Can only go up to 4096×2160.

Container limitation with 360° Metadata tool:
.mp4 .mov

Codecs I can use that surpass 4096×2160:
VP9 | Can’t add metadata to it
h265 | Can’t upload to YouTube

If anyone can assist, either in figuring out a way to add metadata to a WebM video, or find a good Premiere Pro preset for QuickTime, then please let me know.

360° 4K fractal
<a href="https://www.youtube.com/v/P987pD8ulSw&rel=1&fs=1&hd=1" target="_blank">https://www.youtube.com/v/P987pD8ulSw&rel=1&fs=1&hd=1</a>

Stereoscopic 3D 360° 4K fractal [technically 2K because of 3D split]
<a href="http://www.youtube.com/v/9Kx4jHasD7o&rel=1&fs=1&hd=1" target="_blank">http://www.youtube.com/v/9Kx4jHasD7o&rel=1&fs=1&hd=1</a>

Thanks in advance and sorry if this seems obvious - I'm new to fractals! =D