There are soil drenches that can be used to kill off bugs, but I've never used them and don't know anything about them, except they exist. Beneficial nematodes control a lot of soil borne pests. I know they work, but if your problem is root aphids, they might not be enough.

There are a lot of bugs in soil that don't do anything, positive or negative, to cannabis plants, so trying to identify them would be a good idea. I can't see anything from the video. Try one of these, or similar: https://www.amazon.com/Microscope-M...ords=digital+microscope&qid=1630006602&sr=8-3

Look up root aphids and learn what they look like. Also look up fungus gnats, which are a nuisance, but really don't bother the plants (except they get themselves stuck on trichs and die). I actually use nematodes regularly for fungus gnats.

Diatomaceous Earth. Apply with a https://www.amazon.ca/dp/B086H67ZZW...t_i_7PW1QFFXT6NWQN334G8H?_encoding=UTF8&psc=1

Garden supply store. Amazon. It comes in 50 pound sacks. Or small bags for people that eat the stuff.