Hi all! PSA: we experienced drift with two of our joycons (the left ones) and we found a solution that worked for us without sending them for repair!
If you can find electronic contact cleaner (we found ours at a small hardware store - still deemed essential), you can lift the skirt on the joystick and spray some, then let sit for an hour or so. Worked like a dream to clean out any dust. Might take a few tries, but since our second cleaning we've had no issues. Much better than not having joycons for weeks.
Hope this helps!!