They can’t declare victory, only project. Personally, I’m suspicious of the results, but if nothing changes, if fraud is not discovered, it’s a fair call.
The media in this case is using approximately grade 6 math skills to tally up electoral college votes and declare that beyond most reasonable doubt Biden won. I think you're overestimating what their role is here. They were also very cautious and could have made a declaration earlier than they did.
