So basically

1)bitmain had and still has the ability to cheat on hashnest. edit bitmain may not own  hashnest anymore
2)bitmain had and still has the ability to cheat on bitdeer.
3)bitmain had the ability to use its covert asicboost.
4)bitmain and others had the ability to manipulate the tx fees as per this thread https://bitcointalk.org/index.php?topic=2634505.0

and not only did that ability exist I had concrete evidence that  was being done by various pools back in 2017