Hi
sorry I don't know Unity well enough to know what the options are but I would guess one or more of the following might be possible:
Create a public link and then use that link or perhaps embed code in the Xerte embed content page.
Export the Unity package put online and again use that link in the Xerte embed content page.
Export 360 images from Unity and use in the Xerte 3.10 360 image page. This was made available in Xerte 3.10 and I'll past some direct links to sections of recordings where we have demonstrated some of the possibilities.
You would need to get support from your colleague or from Unity as to which of the above is possible or bet according to your needs.
Fay #xerte21 360
mediaspace.nottingham.ac.uk/media/t/1_xzklejog#t=22:06
Ron #Xerte21 360
mediaspace.nottingham.ac.uk/media/t/1_fheqk82m#t=19:13
Ron Future Teacher 360
youtu.be/2tI7bCO9N-Q?t=2115
HTH
Ron