Oh it has to be Federer. The factual GOAT now, and forever the GOAT in my heart as well.
As a Serb, it really pissed me off how people in my country who started watching tennis when Đoković came into power expected all of us to drop supporting our other favorite tennis players and start supporting him instead, or otherwise we're "hipsters". I'm sorry y'all, but in the past ~15 years I must have cheered against him over a hundred times, because there's at least dozen players I prefer to good ol' Nole. Plus, I've been more exposed to his weird woo-woo personal views than the average member of the English-speaking public over the years.