I don’t think you can get an objectively truly bias free news source nor bias checker. If you find one you agree with and people you trust agree with then that’s good for you. You can’t expect everyone else to conform to the same outlook as you. Regardless of which authority figures lauds it.
I don’t know anything about the raters’ objectivity but I asked for evidence and you did provide them. Touché.
What we need is a website that checks the bias of media-bias-fact-check-websites.
MBFC is a gold standard.
https://mediabiasfactcheck.com/about/
Likely, you want a way to feed confirmation bias when the facts don’t support your narrative or view. For that, a bias or fact checker won’t help.
But if you really don’t like MBFC, then you could also check out All Sides and Ad Fontes Media.
I don’t think you can get an objectively truly bias free news source nor bias checker. If you find one you agree with and people you trust agree with then that’s good for you. You can’t expect everyone else to conform to the same outlook as you. Regardless of which authority figures lauds it.