New machine - no virtual terminals

I recently put a new machine together using an AMD Radeon PRO W6600 Graphics Card. CPU is a threadripper pro. Motherboard is an ASUS Pro WS WRX80E-SAGE SE WIFI II sWRX8 E-ATX. Software is the KDE spin of Fedora 37. It mostly works perfectly, but if I try to access a virtual terminal with Ctrl-Alt-F3 my monitors go to sleep, so apparently the video sync shuts off. Typing Ctrl-Alt-F2 brings me back to my KDE session. Also Ctrl-Alt-F1 shows me the text that occurred during boot - I have rhgb and quiet disabled in my grub configuration. So Ctrl-Alt-F1 and F2 work, but F3 and above do not. I don't see anything in /var/log/messages that would give me a hint as to where to start with debugging this. I've tried running SDDM in wayland and in x11 modes, but that doesn't make a difference. I'd like to write a bug for this, but I'm not sure how to gather enough data for a meaningful report. Are there some kernel options I can try, or other ways to get more data? Steve