1000W PSU and Win11 Pro. System will power on, but will not advance beyond the Dell Splash screen. No beeps or blink codes, and system halts after several seconds (splash screen remains displayed but Ctrl-Alt-Del, F2, F10 stop working). I have reset the BIOS, and confirmed that Resizable BAR and Above 4G are enabled. I have also tried booting with ReBAR disabled (as well as a host of other toggles, such as disabling secure boot. I can't seem to get it to work at all. BIOS is up to date.

Ideas?