My dashcam setup in one of my cars is such that both the front cam (Aukey DR02) and the rear cam (Mobius with a modified lens) are both connected to my factory nav screen via a/v ports. The setup alows me to switch easily between each cam, stereo, nav, and other car and entertainment features, including the ability to mirror my iPhone. Not suggesting that this scenario would achieve what you’re looking for, but it might be informative to you in some way.
Note in my video below @00:25 taken at 3AM on a semi-country road that the Mobius seems to illuminate the road behind me far better than the brief shot from my iPhone 6s. This was taken 4 years ago, so I can’t remember if that road is really that dark (I no longer live in that state) or if this is the result of a poor camera. In any case, the Mobius illuminates the road nicely (while the Aukey oversaturates). I still have the same car/camera setup so I may do a couple of targeted tests to see if I’ll see similar results on a comparatively dark road, but this time with a better camera for night vision (iPhone 13 Pro) for comparison.
I’m also thinking of taking one of my $25 internet-connected Wyze cams which have a decent IR setting for night vision for the ride. I would tether the cam to my phone’s hotspot to get the internet feed from Wyze, then mirror it to the nav screen via the Wyze phone app, effectively producing a similar result wirelessly. I’d probably have to stick the Wyze cam out the window to prevent the IR reflection on the windshield.
So, in theory, if something like that works, that could mean myriad relatively cheap alternatives, though probably neither elegant nor practical and not necessarily for dashcam/recoding purposes (cheap IR camera, mounted outside on car/front grille, connected to some sort of nav screen/iPad inside, etc.).
Screenshots