I'm saying 16-17.9M. I think the people who chose 20M or over are very wishful thinkers. I don't think there has ever been a console that sells over 20M in their first year. In fact, selling 20M in a single year isn't necessarily the most common thing for consoles anyway. I think the Wii, DS, PS2, Switch and PS1 are the only consoles that managed that. I'm not sure about the Gameboy, but I'd imagine that one did too. Still...that's six consoles out of the history of the videogame industry.
Expecting the PS5 to hit that mark in it's first year when sales are often lower than their peaks is just not likely, IMO.