KISSmyOS , 7 months ago (edited 7 months ago)

What happens if you press Power + volume down? That should take you to recovery mode, which has a menu entry to boot into the bootloader.
Also, what happens if you just press power?

I had the exact same issue on a different phone, but it had a Mediatek chip. For those, there is a tool “SP flash tool” that can flash the stock ROM even if the phone can’t enter fastboot mode. Once it’s unbricked, you can install something else again.
There seems to be a tool like that for the Zenfone too.
WARNING I have no experience with this tool and don’t know whether the following link (1st Duckduckgo result for “zenfone flash tool”) is reputable:

androidmtk.com/download-asus-zenfone-flash-tool

If the tool isn’t available for Linux, you could try it from a Windows VM with USB passthrough.