Can't export 5760x2880

It looks like this has been covered before, but no solution works for me:

https://discussions.apple.com/thread/250430782

My project has custom settings of 5760x2880:

I am able to work on my movie just fine in this resolution, but when I go to share the video as a master file, the highest resolution is 4096x2048:

The reason I need 5760x2880 is because this is a 360 degree video and this is the native resolution -- it will be imported into a 360 degree editing program (Insta360 Studio 2020) where I will complete the project and export to 1920x1080. But it's important to get that 5760x2880 resolution while I'm working on it.

Any tips on how to export from Final Cut Pro at 5760x2880?

Thanks!