TP2 on the driver board for +5VDC. That's as close as you are going to get to +4.5VDC. ...as an alternative you can go to the J118 connector pin 4, pin 3 is ground.

I am assuming this topper doesn't drop much current, but I don't know anything about it - this is all at your own risk. I can't advise well enough to say you can or cannot add this directly to you 5VDC, let alone what modification you might use. Attaching anything to a game without knowing its specifications of current draw is not advised.

My brother had an LED wall clock that he brought to me to repair, it used 3 1.5V AA batteries for 4.5VDC or a wall adapter plug 120VAC to 9VDC for alternate power. Inside the clock, it's circuit contained a 3.3V regulator - that is part of how it was able to use either a 4.5VDC source and a higher value 9VDC source. So, the 0.5V might not matter. You might even consider a separate source using a wall adapter as below, but in any case, you should know the current draw of your mod before attaching it to your game.

https://www.amazon.com/Parts-Express-4-5-500mA-Adapter/dp/B0002MQGF4