I always remembered Anakin being denied the rank of master because Palpatine appointed him on the council as his spokesperson or representative.
But the Jedi did not trust Palpatine at all. They had to let Anakin in, but they didn’t grant him the rank of master because of a lack of trust.
They even asked Anakin to spy on Palpatine.
Maybe I’ll have to rewatch the movie to fully remember.