I don't see a video attached, just two still pictures. But from the description (game character walking or moving without any input), it sounds like stick drift.
Not sure if that is indeed the problem, but it's a known issue with joy-cons and Lite switches. The recommended fix is to have the sticks replaced. Other workarounds, like cleaning them with compressed air, or adding shims, may delay the issue but not for long.
Aftermarket replacement sticks can be found online for cheap, but most will eventually drift, too. The best ones use either Hall effect or TMR and cost quite a bit more, but will never suffer from drift. I've had good results with the Gulikit brand.