Of all Trump's picks, this IMO is one of his weakest ones.
The SECDEF plays a very high-impact role in some very high-stakes crisis management situations that sometimes come with very short timelines to act. If there is a single cabinet position that demands relevant experience, in this case in the upper echelons of military leadership, the SECDEF is it.
For example, he carries the backup nuclear football and the president has master override codes for the nuclear triad that he can give SECDEF in the event of a major conflict/event of if he's ever in danger or cut off from communication w/ CENTCOM. That means that the SECDEF, without the need for future approval from the President or anyone else, can be granted the unilateral authority to launch nuclear weapons or some other response against a hostile actor in a crisis situation. The understanding one needs of our military capabilities, strategies, and tactics (as well as that of our adversaries) to handle that responsibility is immensely important.
There have probably been a lot of underqualified folks in the position throughout history, I'm not saying he's the first. I'm just left wishing for someone a bit more experienced and frankly qualified for the role.
I'm not attacking the platform he's pushing in terms of preparedness, anti-woke, etc. He just seems underprepared for what the role hopefully never has to manage but could during his tenure.
I'm not attacking him as a person by any stretch, just putting my concern out there.