Federer is the best of all time, but not the GOAT. The real GOAT doesn't exist. He would have to be the BOAT + own the best H2H against his biggest rival.
Since Nadal IMHO can never have all the records in tennis like Roger, but he isn't a BOAT, much less GOAT candidate.
Roger is as close as it gets.
But peRFection can never be attained in this world.