I had a huge problem with the left analog stick drifting without being touched on my first pair of joy cons, which led me to buy another pair. Then the same thing happened. I was actually on the verge of buying another pair, or at least a left joycon. But, I looked around online first for other solutions. I watched a video from Spawn Wave about opening up the joycons and replacing the analog stick yourself. Before considering that, I also saw other people mentioning spraying under the analog stick with contact cleaner to dislodge whatever debris particles might be causing the drifting. I had a can of DeoxIt in my house, so I sprayed around the analog stick of both misbehaving left joycons. It eliminated the drift problem from both analog sticks. That was several months ago, and the problem hasn't cropped up since fortunately.
Do you have a link to those videos using contact cleaner? My sister has had issues with the joycons and I already bought a replacement analog stick, but that solution you mention might be easier for her to perform.
EDIT: This is something I might need to do soon, my joycons are already out of warranty, but I noticed one of my right ones the plastic latch is broken again... maybe one of my nephews did it :/
Will have put these metal ones someday