Why does my LED light take several minutes to come on?
The driver circuitry May have been damaged or had cold solder joints that are failing.
The led dimmed or not should be almost immediate.
I have had drivers that had cold solder joints on very high end fixtures that caused the fixture to take longer to light to start with and a while later it would not light at all as these fixtures were almost 500 ea I figured out the problem and it a bad solder joint (I don’t have to mention where the fixtures were made but it was not the US)
If you still have a warranty I would recommend trying that route because if any LED won’t light in under a second something is wrong.
I would also recommend getting DLC approved lamps or fixtures DLC is design Light Consortium and they usually have a 5 year warranty (some 3 year) .
All the ones I have seen also have UL listing (I have to have this for industrial or another nationally recognized 3rd party facility).
Since the lights are taking more than a second there is a problem it could be a loose wire can be a possibility. My experience has been bad drivers on almost 100% of my failures.