Yes hikaru could have, but he didn't, if you watch the stream. He doesn't have engine analysis on while hes looking at lines. It's off the cuff analysis without engine help.

Like compare hans to alireza in their interviews. Hans clearly just has a worse understanding of the position he chose to go into.

I mean to me it feels less like cheating and more like just absolutely wild prep, hans played like a 3200 up to the midgame and then couldn't convert a winning position, but it's suspicious to have such completely insane prep, especially without clear compensation