Many of these experts are missing the slow aspect of the FO conditions and focusing only on the low bounce. The low bounce is a disadvantage to Nadal as his topspin stays in the hitting zone of his opponents instead of jumping to head-level quickly. But, the heavy, slow conditions are making it impossible to hit through his defenses which favors him. He was always the best defender on clay even in hot conditions and now, he is even better.
One of the main reasons that Nadal is dominant on clay is because he takes away the will of his opponents to keep fighting because he grinds so well and plays fantastic defense on every rally - they stop wanting to fight after a while subconsciously. I think this aspect of his game is helped by his conditions and we saw what happened to a heavy hitter like Sinner in the third set (breadstick!) after a couple of closely contested sets.
I think Djokovic will try to hit through Nadal if they play in the final as he has never had the patience to outlast Nadal on clay. Djokovic always plays more offensively than usual against Nadal on all surfaces because he knows that Nadal is a better counter-puncher than he is and so, he has to take the initiative. His serve is usually a big part of why he wins against Nadal on other surfaces. In this tournament, serves are neutralized and this favors Nadal even more. In addition, there are more longer points than usual even for clay and Nadal is winning 65% of rallies that are more than 4 shots. Even if you win 55% of all points in a match, you usually have an easy win and so, the high number of longer points being played favors Nadal also.
Based on all that, I disagree with McEnroe and Goran that the conditions favor Djokovic.