I know someone in this field and sent him this article. He said the “NIST isn’t being transparent” claim isn’t true
https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=927303 https://nvlpubs.nist.gov/nistpubs/ir/2020/NIST.IR.8309.pdf https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=934458
He also responded with “of course the NSA would try and mess with it, but if it’s peer reviewed properly I don’t see how they would be successful”