Worth noting that these transcripts detail Trump forcing 12 year olds to act out lesbian sex while he watched, then give him sloppy head. And apparently when the BJ was kinda toothy (cuz, ya know, they’re 12,) he got angry and physical.
But sure, let’s elect him as king of the United States.
But notably, it does shield them from prosecution for crimes which are tangentially related to their official duties. For example, granting a presidential pardon is an official duty. Taking a bribe in exchange for that pardon would be a crime. But now the president is allowed to openly and blatantly take that bribe, because the bribe is tangential to their official duty, and they are therefore shielded from prosecution.
Many experts disagree with the second half of your sentence, because ordering an assassination could easily be argued to be an official duty; After all, the POTUS is the commander in chief of the military. According to this ruling, ordering it illegally would be protected, because the illegality is tied to the official duty.