Someone reviewed that specific paper here [1].
[1] https://web.archive.org/web/20220128195023/https://motls.blo...
[1] https://web.archive.org/web/20220128195023/https://motls.blo...
On their arXiv page: https://arxiv.org/abs/2006.12546, the author states that "though all my previous proposed (dis)proofs were flawed, i think the flaws pointed me towards the right direction..."