I don’t deny the existence of a mainstream media bias against trump, but all of the things you listed weren’t really all that secret. I and everyone I know knew about those things and they weren’t exactly following things super close.
What the media, both the social and traditional varieties, did to Trump is disgusting and goes way beyond bias. It was a targeted campaign with the goal of undermining and removing him from office from the moment he won the election. Propping up and protecting Biden was a means to an end.