clogging in the feed cog, move the printhead to different positions and chack the filament goes through with the tube in different positions.

If none of this makes any difference buy a new board. A mks gen is about $20
Or you can get a direct replacement for $50

Looking at the creaity board - it's pretty basic.
The mks gen L has all the same connectors, but no card reader. presumably you're using the card reader on the screen ? in which case it doesn't matter.
Oh yeah and the gen -L also uses replaceable stepper drivers.

Never hurts to have a spare board around the place :-)