DIY duct cleaning

HVAC tech turned homeowner haha I bought a crack house and the ductwork is so filthy. Hunks of dust and black cob webs.

I’m thinking about cleaning the ductwork and was curious if anyone in here had suggestions. It’s a classic 80’s thermopride octopus setup.

I was going to disconnect the runs to the plenum one at a time, tape the hepa shop vac we use for core drilling on it somehow, and then from up top at the boot I make a contraption out of a chunk of fishtape and some tstat wire in weed-whacker formation, chuck it in a drill and let it rip down the length of the duct with the vacuum running.