Experts have been skeptical for quite some time. You can see discussion on the exact point Scholze (PS) brings up in the following blog post (the post and many comments are by prominent number theorists)
> This post is not about making epistemological claims about the truth or otherwise of Mochizuki’s arguments. To take an extreme example, if Mochizuki had carved his argument on slate in Linear A and then dropped it into the Mariana Trench, then there would be little doubt that asking about the veracity of the argument would be beside the point. The reality, however, is that this description is not so far from the truth.