Like you said yourself even the Xbone despite the controversy that haunted it at the time sold more than the Switch in its first two months, so its very hard to imagine a scenario where both of the new consoles don't do the same.
If you want specific predictions I'll say:
PS5 - 5,6 mil (assuming it launches in Japan right away unlike the PS4)
Series X - 3,7 mil
Try out my free game on Steam
2024 OpenCritic Prediction Leagues: