No evidence, but what is different this time is an actual legal complaint with the IG with a lot of info the public can't see. Grusch's claims are fantastic and sound down right crazy, but his story has stayed the same. Plus with him being an intelligence agent for years with multiple government officials saying he's been trustworthy in the past.
I look at it as either there's some faction if the government that for some reason wants us to believe there's aliens or he's not been fed lies and there's aliens and both are pretty interesting. It also was pretty bipartisan in the hearing, I was pretty surprised to see AOC there instead of just a bunch of right wing war mongerers looking to use it as an excuse to bump military funding a bit more, and she had some great questions for Grusch.
Unfortunately if everything he says is true it would be all classified so we wouldn't hear it yet anyway making it convenient to lie, but why have a legal complaint with the IG if he just wanted to lie for fame? We've seen other UFO grifters make tons of money from people with way less effort. It's far more interesting than the normal UFO stuff just because everything seems to be handled so properly for an absolutely insane claim and either way it's going to be interesting to see what is going on, if we ever do.