I believe you can make an adapter that goes from a 5-pin JST NH connector (I have no knowledge of the pinout for original Model 2) and then just wire that to a DSUB-15 breakout or connector with R, G, B, Sync and GND. I've got a Nanao FlexScan 8060S (super old, from the late '80s) that works fine like this on my Model 3s using the 5-pin header. Unfortunately there are some bars even after adjusting the pots below the monitor to my liking, but I bet there's a pot inside the chassis that can tweak it even further.
I've been wanting to make a compact House of the Dead 1 setup and try playing it with the Master System Light Phaser (it's just a DB9 connection with +5V, GND, Trigger, and Sensor), but the boardset is expensive and super high in demand right now. My Gun I/O is also giving a fit where the video's a squiggly mess (in Virtua Cop 2 Model 2A ROM Board).
