You can split your screen in Unity by adding a second camera and setting the rectangle for each. You will obviously want to position the 2 cameras the correct distance apart for vr.
There are plenty of search results "unity split screen" if you want more detailed info. Eg: https://discussions.unity.com/t/how-to-make-a-split-screen-2-cameras-rendering-at-same-time/307
Also, have you tried Unity's open xr package? I've read that you can use Google daydream as a PC vr headset if the daydream packages aren't working for you https://www.xda-developers.com/vridge-2-2-google-daydream-steamvr/