The latest KDE .ISO was burned to a USB Flash Drive yesterday, would not boot to livwe Front/ack same thing, it would almost get to DE, but stop at a blue/green blank screen a bit color blind I think. Then we tried a dvd, same. Sec. boot is off, boots Mate fine. The sys that burnt it booted the live install fine.
Did you check ISO Image For errors before creating USB ?
What did you use to create USB ISO?
Have you tried using ventoy to format USB drive so that the ISO can just be copied to USB drive?