I'm pretty sure you need to rename the bones, which I do remember writing in the tutorial, although I might not remember if I said that you have to rename them first before reposing, but make sure you do that
I did rename the bones, and just the left leg and spine have errors,s but still won't work, so I did it manually, and I noticed when going to turn off relative rotations the xyz are off, like one controls the y when it's supposed to be the x
The relative rotations are hard to get working correctly for every model it seems like unfortunately as even a lot of 3D modelling programs struggle with this as I have seen, although rotating them globally seems to work better in comparison.