Might be DisplayID problem:
I had similar problem.
EVGA 3090Ti (recently purchase)
I did not have problem with my LG monitor when it was paired with 2080 Ti. As soon as i install EVGA 3090Ti, i cant see boot screen at all until windows.
mine was fix with Nvidia Vbio Display ID bios fix.
I have the same issue. Found that using a different older hdmi cable it would work fine but using my new hdmi and DisplayPort cables I got just for 4K, it wouldn’t work or had the problem you discribled. Also would sometimes make a beep code at boot 1 long 3 shorts meaning no gpu detected. Going back to old hdmi everything works fine so suspecting a simple kind of bad cord, or a firmware issue with the 1.3 or 1.4 versions that get it up to 4K.