Re: Since media projected
The official results aren't known until the Electoral Collage votes are tallied on 6 January 2021. Obviously media don't want to wait until then. Instead they look at the popular vote in each state. If one candidate has more than 50% of the votes cast, they can call the result for that state without waiting for all the votes in that state to be counted. Multiple that by the EC votes the state has, and they can sometimes call the whole election even before each state has been called. Being media they each want to publish the result before any other media, so some of them use projections to get an edge, such as relying on the distribution of uncounted votes being similar to ones counted. I think most are actually more conservative, and use objective criteria, but we did have some differences between the early media proclamations.
The same happens in the UK. We use constituencies rather than states and an electoral collage, but the effect is similar. Get more than half the constituencies and you've won, and any remaining count will only effect how big your majority is.
It's unlikely that a respectable media like the BBC would be influenced by which candidate they preferred in this. Nor is it clear what they would gain by calling an early but wrong result. I expect a win for either candidate would get the same number of clicks.