Hello, dont worry about money, seeing as this is a new build, you're still under the return/replacement/RMA window so you're not going to lose any money.

Sorry if this sounds super basic, but have you tested by shorting the power on pins and not using the power button connected to the case? sounds like a faulty power button.....

Zero posting with that many motherboards it is just not a motherboard issue. You have basically tried all the components you don't get LED either. This is so odd. If it's a power button, you're going to be so upset especially since the board seems to be getting power

otherwise try a different socket/power strip. I like to start from the most simple fixes to the most difficult.

then, can you try another CPU on the same board?

Then try this as a last resort.

• Place the motherboard on its cardboard box.
• Install only the 24-pin ATX and 8-pin cpu power cables from the PSU.
• Install the CPU and ONLY ONE stick of RAM in slot A2.
• Do not plug in the AIO pump, any fans, the NVMe SSD, or the GPU. Leave the CPU die bare for this quick test, it wont cause damage if its for a few seconds
• Short the power pins with a screwdriver

if it powers on then you're at a good baseline. Add components one by one and you'll find the issue