How to apply mixamo animation correctly to a readyPlayerMe character

Questions
1

I’m posting this question similar to the one you can find here: question, Unfortunately, the previous discussion didn’t help me resolve my problem

I’m trying to apply animations from Mixamo to models from ReadyPlayerMe. The only restriction is that I don’t want to adapt the models to the animations but rather the animations to the models. The purpose of using ReadyPlayerMe is that I need models to be load from the web.

I noticed that the bone names for the Mixamo animations don’t match those of the ReadyPlayerMe models, so I modified the bone names of the animation in Blender to match those of the ReadyPlayerMe models and this what not an issue. However, after loading both the modified animation and the model, I’m getting a rather unsatisfactory result.

I don’t know where to start to resolve this issue. Does anyone have any advice?
(the animation is not a root motion animation)

2

It looks like this problem can be caused by unchanging scales. Is the actual animation playing on the character model while it is bouncing up and down?