It's exceptionally likely Trump was kept away from as much intel as they could reasonably keep him from. We know that from things that leaked out after the fact, eg by how General Milley behaved (gave orders to disobey nuclear launch commands coming from Trump).
From what I’ve heard, it’s not like he was even interested in the intel he was supposed to be interested in.
If Trump knew there were Aliens there’s no way he could have kept himself from blabbing all over Twitter.
Friedman had an ex CIA guy on his podcast and he explained how the daily intelligence report worked. Basically the president told them which things he was most interested in. That was in the front and the rest was more CIA judgement.
The CIA is (supposed to) serve at the pleasure of the president.