The general response in this discussion is skeptical, and I can understand the hesitation to broach the UFO/UAP topic, particularly when the topic has been vilified for literally decades. However, we are now in a legitimately different era of discussion of these topics, and you have to be willing to open your mind to the idea that these efforts are legitimate.
The bipartisanship at the hearing is to be commended, and the national security angle cannot be overstated. All three witnesses believe these UAP are genuine national security threats because they possess flight capabilities far exceeding anything beyond what we have. These UAP were documented on multiple military sensor platforms, some of which are still classified.
You must realize the USG has been and is engaged in an active disinformation campaign to deny existence of UAP, even to Congress. For example, multiple Subcommittee members mentioned that they wanted to meet in a SCIF with Grusch to receive a classified briefing but could not. A direct quote from the hearing: "Just so that the press knows and the people know, we [members of the Subcommittee] were even denied access to a classified briefing in a SCIF due to the amount of hoops we had to jump through to grant temporary clearance to witness Grusch, who has knowledge of classified information." Additionally, multiple members of Congress were initially denied access to data and personnel related to a UAP incident reported at Eglin AFB and in the end only received a portion of what was sought. Clear attempts to prevent elected officials from merely accessing relevant information is a genuine threat to national security because the military serves the people, not the other way around.
All three witnesses are trained and decorated military service members, each of which have since left the military. Their situational awareness and observational abilities are much better than you or me, particularly since we haven't been explicitly trained on such while they have. Additionally, Grusch is documented to have worked in both the National Reconnaissance Office (NRO) and National Geospatial-Intelligence Agency (NGA), two sensitive branches of the military intelligence community. As far as I'm aware, the NRO ships and provides military sensing platforms, and the NGA performs analysis from many different military data streams, including the NRO. Grusch even said in his opening statement that, at the NGA, he had a hand in making the Presidential Daily Briefing.
One commenter here says it's "more reasonable to assume this is psyops by an adversary", which is, by definition, a conspiracy theory, given that the commenter has no evidence of such occurring and would prefer to live in a world where three former US military service members are coerced to commit perjury to Congress about something which doesn't actually exist. Moreover, if an adversarial nation possesses craft with the capabilities described by the three witnesses, drawing any attention, even through an active disinformation campaign, to that strategic advantage is a clear breach of operational security with no clear, tangible benefit.
The preponderance of evidence in support of the existence of UAP should be overwhelming unless you've made the choice to not accept the premise: that intelligent life beyond humanity exists.
Here's a link to the full hearing recording: https://www.youtube.com/watch?v=KQ7Dw-739VY