One idea would be to buy out the investor. I read in one of the comments that you do have some cash to spend. If you can work out a reasonable deal with the investor you would no longer have a neutral party doing nothing, you'd own 50%, and be able to set the terms.
To get there I think the GPU will have to be embedded in the monitors, and some interesting operating system hoops will have to be jumped through. Do cords have enough bandwidth now to support this? I honestly don't know the answer to this question. I feel like the answer is yes.
The other idea is just to mount the phone to a head mount display and go VR or AR. But I feel like that is going to require way more advancement in resolution on the phone screens to get right.
We can get there. We are super close. The iPad with an M1 chip probably already has the power to do it. Maybe one or two more years and this is not only feasible but purchasable. I'm a buyer.