(ちょうてん) Can mean the apex (in a mathematical sense) or the peak of a mountain, but usually refers to a brief period of time when something is at its peak (the peak of his popularity, the breaking point of public outrage, etc.) Also can sometimes refer to the high point of a movie or book.
(みどころ) The highlight (of a work of art). This can also be used to mean the climax.
(ちょうじょう) The summit – of a mountain, but also can mean the top of a hierarchy or a “summit meeting.”
(さんちょう) Top of a mountain more of a geographical, term than 頂上(ちょうじょj), and not as formal/literary as the related term 頂(いただき). You’d point to a 山頂 on a map, but if you wanted to say “The view from the summit is gorgeous,” you’d use 頂上.
(てっぺん) The summit of a mountain, OR a tree, or even the top of one’s head – usually used in the phrase ‘from head to toe.’ A more blue-collar word than the related term 山頂.
(いただき) The summit of a mountain. A sort of literary or formal word.