For some of you knowing how to properly use backdrop-filter, there is 3 years old chrome / chromium bug where one of two nested filters don't work. It includes opera but work fine in Firefox.

More about the bug: https://www.reddit.com/r/Frontend/comments/xm2ft0/cant_get_backdropfilter_blur16px_to_work_in/

Even ChatGPT don't know about it, so I post it here for others.
I wasted 2 days searching my problem.