Your steps to find the error are exactly what you should do, so nothing wrong on your side. Next I would try to use a different SD-card and if this does not help a different power-supply. Note that for a bare Pi4 you don’t need a 3A rated “Pi4”-supply, anything you have with 2A will do (as long as it has a usb-c plug).
Unplug any USB devices and try again. My Pi 4B would not boot up if my Wireless Keyboard dongle was plugged in.
Also, if you remove the SD Card and boot up you will get a diagnostics screen, that may clue you in to what’s going on?