Please follow the optional step in the post regarding the profile. This will allow you to raise the FOV above what is possible in the game and solve your issue.
I’ve followed the optional steps but NMS still appears inside a rectangle instead of me being inside the world, most like cinema mode with borders outside the rectangle.
Try hitting the button that’s bound to edge peek maybe? Perhaps it’s starting zoomed out like that. Or try using the keyboard commands to navigate the vorpx menus. Maybe the zoom is set low or it’s letterboxed
If you still see borders with the above settings, you can raise the Image Zomm in the vorpX ingame menu above the proposed ~0.6. That will also require a higher FOV in the .ini file though, which will have an impact on performance. So you need to find the right balance for your system.