Burning smell from electrical panel

SconesyCider wrote:
So here is the skinny...snip

Negative screw terminal has some wiggle to it.

I’ve noticed that the lights have been intermittently dim with a light flicker from time to time.

There is a clue in what you said about the negative terminal;
If the main ground wire is loose there, then you will get an increased resistance and it will heat up there. This will cause the symptoms you describe.

This needs to be addressed sooner than later. There is a fire potential with a loose ground.

Disconnect all power, shore and 12V (I know you have the battery out of the mix, but be sure its not connected.)

Then loosen the ground terminal and pull the wire out of it. Check to see if it is blackened. If you have enough slack, cut the end off and bare a new part of the wire, ensuring it is clean and bright copper in color. Pull the terminal screw right out, try to get in where the wire goes and scrape it clean with a tiny screwdriver or similar, scrape the end of the terminal screw too.
Put it back together and make sure the terminal screw is very securely tight onto the wire.

Really important to have a good solid ground.

But of course, if your converter is on its way out you will get this issue too.