I don’t understand the reason behind your problems.
I don’t understand the reason behind your problems.
Your MicroATX case restricts you from inserting your GPU into a different PCIe slot, but it still fits into the PCIe 4.0 port.
You're adjusting the PCIe version in UEFI to 3.0 for a specific slot to test its effect. It's unlikely this will help after OS reinstallation if you're encountering POST artifacts. The GPU usually handles its own PCIe version during startup, which the CPU might find challenging for various reasons.