No display after macOS bigSur install - Mac mini 2018

I successfully downloaded and installed big sur, but after system asked me to restart it never appeared with a display.

after an hour I tried a restart and after that SMC and NVRAM resets, even tried usb-c hdmi dongle for display instead of hdmi port, nothing seems to work.

any ideas...?

update: I hooked it up with hd tv and it worked, what could be failing in making my actual monitor work as before and how to fix it?
No display after macOS bigSur install - Mac mini 2018
 
 
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