McDavid and MacKinnon are definitely ahead at center. Drai has such an offensive gap he's probably there too in general, but head to head? Not sure...
Crosby at this point in his career is slightly below. Matthews is bonkers in the regular season. Talent wise, I think he has Barkov beat maybe, but Barkov is ahead defensively. So far, Matthews is a playoff no show.
In short, I would say it's not wholly unreasonable to regard Barkov as top 3. Top 5 is more than fair.
Therefore, I would say he's only overrated if you place him at 1, which most don't.
How is Eichel better than Barkov at this point, exactly? He doesn't have the numbers or the defense. Also, Crosby doesn't really have an edge offensively anymore.