On power on, the keyboard flashes once with no boot

Hi, I have an Asus Vivobook 14x OLED m5402 (was autofilled to the product listed, which I'm guessing is a very similar machine).

The laptop was working fine (no issues) over the weekend, but when I went to boot today only the power light turned on and fan started spinning with no other changes.

I tried using the reset where you hold the power button for 40s then plug the laptop back in to the power adaptor and now the keyboard backlight flashes once on power-on (quickly) then I get no additional feedback from the device.

I have also tried using an external monitor via HDMI in case it was a display issue, but unfortunately had no luck.

Are there any other additional steps that are recommended for self triaging?