I went down into my basement shop to mess with my JTech 2.8W setup a little and there are times where I don’t use my laser for an extended period of time and when I go back to turn it on I have to press the red reset button on the JTech Driver. When I went to go turn on the laser, I had to press the reset button initially; but then I tried turning the Shapeoko on and off and it didn’t trip the reset, so I’m not entirely sure what causes that. I don’t seem to have the same issue of needing to unplug/plug anything. Are you unplugging/plugging the input cable at the Carbide board or at the JTech Driver? When you’re turning the Shapeoko off and on, the laser requires unplugging/plugging every single time without fail?
When you say, “the laser will not turn on correctly” are you saying it doesn’t turn on at all until unplug/plug back in or it turns on and doesn’t have full function? I understand you checked your wiring, but you still could post pictures of your wiring/boards for an extra set of eyes just in case something may jump out at someone else. I’m wondering if there are connector issues that re-establish a good connection when you plug back in.
As far as your power issues, I’d double check your LightBurn settings and confirm that GRBL setting $30 = 1000 because that would directly affect power output. If Max Spindle RPM ($30) is set correctly at 1000 then I would start to look at focusing your laser to confirm that’s good. Before you double check focus you can also confirm the lens is clean (laser off obviously - sorry had to throw that in there). If your power settings are ok and your focus is good then you could look into confirming voltage output at the Carbide board PWM, I believe it should be 5v max output. Another thing to note is smoke extraction while using the laser, do you have a fan mounted on top of your laser; too much smoke could also inhibit good engraving.
Anyways, hope some of this helps you and you’re able to get to the bottom of all of this.