Short(ground) or eliminating spark(pull plug wire) to one cylinder at a time, if the noise goes away, you found your problem hole/s, and possibly the misfire also if that is still present(based on RPM drop).
You can do this manually at home or take it to a shop with the equipment to data log the rpm drop of each cylinder.
Known as a cylinder kill or cylinder balance test.
I believe your only after a noise at this point? Misfire/shake at idle remediated.
Ignition base timing has been set at this point , correct?
FWIW ...From the video, I hear a wrist pin knock.
Wish you were close by, I'd gladly stop by.
Keep diggin!
