I fixed my dryer, the drum bearing had worn and needed replacing.
To be more specific... the bearing had completely disintegrated, the ball bearings were rolling around the bottom of the cabinet and the drum bolt was just rotating around on the spacers which gouged them out as you can imagine.
Given it was metal-on-metal I would have thought it'd be making far more noise than it was but I guess not.
Anyways, lesson learnt, don't ignore even minor noises. It would have been an $8 fix but it wore out a few extra bits and turned into a $55 fix, but that still beats the cost to have had someone out to fix it for me so that's a win!
The spacer that was acting as the bearing:
