Can't add much to what the pro's have already said.............except to say.......similar event happened at a house around corner from where our first home was. Same type of situation......some remodel work was down........and shortly after that the house burned to the ground.

The cause they came up with was a nail driven into a wall hit a wire.........and the short it created made the nail hot enough it ignited the pine board it was driven into. Apparently the breaker didn't see that level of short as a problem........just a load on the line. If a dimmer switch was melted, same condition may still exist. If it does, I'd want to be finding it at whatever the cost.

My old Electrical Code instructor had a problem with an arc fault breaker constantly tripping in the garage he just built. He went over and above with the arc faults, he doesn’t need them in a detached garage.
Tried a new one, same thing.. He pulled some sheets off and found a bunch of long staples from the crew that sheeted the outside, one bit through his 14/2 circuit. Guess they used up the long staples that were in the gun before switching to shorter ones.
Some folks switch to a normal breaker when the arc faults keep tripping, they’ll hold if there’s not enough of a fault……until it burns itself clear and nothing works, or the fire department shows up.
Sometimes when the breaker trips, it’s not weak or faulty, it’s actually doing its job……lol