How can i export 8k 360 3D stereographic video in h.264 codec with FCPX?

How can i export 8k (7680 x 7680 pixel) stereographic 3D video with FCPX in H.264 codec?

I can do it as ProRes but files are ten times the size - 30Gb for one minute footage.

When i try exporting h.264, i get the error ""Frame size settings in the output exceeds the allowable dimensions of h.264 format."

I know 8k 3d stereo 360 is non standard h.264 codec size but the original was created in Insta360 Pro 2 Stitcher software - so it can be done.

I tried Hybrid Video encoder but no longer supported by Mac.

Any suggestions - other than Adobe Premiere?! :)

Big thanks !