The option for the p4 was a converter module that bolted on. I'm guessing the same is possible via otg, it just hasn't been done yet. I'll keep my eyes open.
what i did using a iphone ,is lightning to hdmi adapter from apple and hdmi into goggles, did not use fatshark but used MAGICSEE but cant see why ANY goggles that accept HDMI would not work tbh ...(i might be wrong but doubt it )
i've found an otg to hdmi cable for my tablet, but then i would have to run wifi to my remote. i guess the only way to have both is to have a tablet with a dedicated hdmi out.