Asus mobos have a couple of things that can point you to the boot problem. I have an X570-E and on mine there are both. LEDs that will show at what point in the boot process things are and if there's a problem in a particular area--like graphics--it'll get stuck with that LED lit. The other way is a digital display that shows what's called a Q code. They're listed in the board's manual and will tell you exactly what's happening.
Do you have another known good video card that you can try in the slot? Does it work? If you try that and it works it could be the BIOS needs updating. Go into the BIOS and restore defaults. Make sure you do this before flashing a new/different BIOS otherwise you may have problems. Reboot.
It could be that the board is using it's OG BIOS which might pre-date the video card and so doesn't recognize it. On my board there's a few ways to flash the BIOS by either a tool within the BIOS (that I usually use) or by using a certain USB port that has a button on it just for the occasion (that I did when the board was new). Both worked fine. Get to a working PC, have a USB stick handy. DL the latest BIOS. It'll come in a zip file that will contain the BIOS and a renaming tool. Unzip, run the tool, copy/paste the renamed BIOS file to the USB stick. Plug that into the BIOS flashback port, bring up the tool in the BIOS, navigate to the USB stick/file with the arrow keys and run the tool. It'll flash the new BIOS and reboot the PC at defaults. Otherwise you can use the flashback port and just press the button. It may take a while to flash the new BIOS--don't stop it under any circumstances! To be sure of the process DL and RTFM so you have the steps right.