New build won't post. Any advice?

Hey all. Just finished putting together my new build, everything's wired up and seems to run but it just won't post. No splash screen or anything, monitor says no input detected. All the lights turn on, the fans are all spinning, I can hear the AIO working, and my keyboard lights up when plugged in but nothing else happens. I only have an M.2 installed right now and it's one from my previous PC that has a Windows 10 install on it, was planning to clear it and install Windows 11 anyways.

Specs are an Asus Prime X870P WiFi, Ryzen 7 9850 X3D, PNY RTX 5080, and 32GB (2 x 16) of DDR5. Any help would be massively appreciated.