Sony will probably have a strong start with the PS5, unless they mess the reveal up PS3/XBOne style. Considering they've been burning some of their consummer good will lately (lateness of getting cross-platform functionality, PS Classic being a cashgrab, increasing censorship on nudity...) it's not out of the question they could fuck it up, though it is minimal they have such a strong hold on the console market.
The XBTwo is going to struggle, both by the XBOne not being that competitive to begin with and due to Microsoft's direction to put their software on other platforms.
The Switch is the only real gaming handheld left in the market, and even at its weakest that has always reached at least 70-80m all platforms combined. The Switch is able to reach and pass that number easily, considering how well it sells due to the strength of Nintendo's IPs alone, plus the ocasional big 3rd party.
No idea how to quantify the Apple Arcade and Google Stadia effords compared to the regular consoles.
You know it deserves the GOTY.