Doesn't matter because who's going to check them? SCOTUS? No. COTUS? No.

Unitary executive theory = plenary powers, e.g., they're a king in all but name surrounded by political loyalists with their hands on every lever of power that matters.

I think the president only needs permission from Congress to officially declare war (or rather only Congress can declare war), but the president is commander in chief of the US military and can do, for lack of a better term, “special military operations” without any approval (all joking aside, I think it means the president can always order military action just can’t declare war against another country, and I don’t believe the US has declared war on Venezuela).

No. War Powers Resolution of 1973.