it always use "and", such as "resolved" and "assigned to xxx"

You can set "Match Type" to "Any Condition" to use "or"

not "resolved"
"assigned to user1" or "assigned to user2"

You can switch to "Advanced Filters" (burger menu on right top of the filter section) for these use cases.

Advanced Filters only allow me to set multiple selections, but what I need is not "xxx"
For example
If I want to filter all bugs without specific label "a", I have to select all labels except "a", that's impossible for me to do.
I can not find any way to set not "a" even in Adavnced Filters

I can not find any way to set not "a" even in Adavnced Filters

Press Ctrl key and click "a" to unselect "a"

I can not do that when it's a label, I can only type some label into a textbox