Apple hears ya, Apple don't care.
Yeah apparently from people familiar with the deep black hole that is Radar you're supposed to keep submitting bugs, dupes count as a vote or something.
It sounds absolutely horrendous.
I once reported a chrome issue. Got no attention until I found a different issue I thought was related and commented there, which got the attention of someone competent who realized it was a hardware bug they'd fixed before but had a regression.
Not a security bug, just that a very large number of websites didn't load.
A+ experience with the Chrome team
E with Edge
F with Safari
The Chrome devs have been astonishingly good. My experience has repeatably been that if they are given a good bug report, they get it fixed and often fix it really fast. Or they reply with excellent technical reasons why not. Also multiple times I have seen extreme corner-case regressions get magically fixed without me reporting anything!
Edge - always waffle and misdirection in reply to bug reports. I only bother to give them very well documented, repeatable bugs, plus attached repro file, for things I really need fixed. However: I did have one good experience recently because I reported the bug for the Edge beta, on a feature they were actively working on catching up to the other browsers (however they still had poor interaction).
Safari: hopeless. Report a critical bug with excellent repro file, and get no response, and no fix.
No rating for Firefox because I haven't bothered reported any bugs to them in the last few years.
Edit: this is for non-security related bugs.