If the media was even only 60% biased Trump would have won.
They spent 4 years trashing him with lies, innuendo, and failure to report his successes. The coverage of him was almost 100% negative. This negative coverage was reinforced and promulgated by academia, hollywood, and big tech.
The sheeple followed. Even then, I still think Trump won the election, but there is little doubt that tens of millions bought into the media lies and narrative.
Being stupid and gullible is not an excuse.