Glassdoor is not reliable. Companies can pay to suppress negative comments.
Are there trusted impartial review sites?
They exist, but are very few - their articles get stolen by unscrupulous copycats, or the AI slop buries them in noise. It's like panning for gold, but instead of a bubbling creek it's sewage runoff. I hardly ever find trustworthy results on the first page any more, you got to go several pages deep until you stop seeing the "Top N you absolutely need to buy!" results.
"BuT mAnIfEsT v3 wIlL pRoTeCt UsErS fRoM mAlIcIoUs ExTeNsIoNs."