You’ve got a good ol’ Cereus repandus aka Cereus peruvianus cactus. It could also be a Cereus hildmannianus, but I don’t know if there is a huge difference tbh;). Here’s a little Info:) on why there is confusion.

Edit: I just looked at the Arizona State University’s public page on Cereus repandus and Cereus hildmannianus, and it says that hildmannianus has “Stems grayish to glaucous”, it doesn’t say that for repandus. So I’m guessing that’s your cactus;). The coloring is the only difference I spot between the the two cactus in question on ASU’s site about the two cactus.

Thank you!