The PS5 had the best launch in history but will it be able to sell as much as the Nintendo Switch knowing that Nintendo consoles have much better sales dynamics than Sony's?

No. It will sell better.

So it really is very early to start making predictions about this, but going if I were to make one I'd say that I don't see it happening unless it has an unusually long lifespan.
In fact at the moment I don't think there's much of a reason to believe it will outsell the PS4, since it will have stronger competition in the Xbox Series (it's not in direct competition with the Switch the way I see it).

Yeah, let's clarify what does Nintendo have better sales dynamics mean?

I mean the Gamecube didn't too well. Wii was a homerun. WiiU bombed. And now Switch is a homerun. Nintendo first party games tend to sell very well. Other than these points, what is a sales dynamic and what does it have to do with Nintendo again?

Who knows, only time will tell, I have no reason to believe Ps5 wont sell 150m and no reason to believe Switch wont sell 150.01m.

Too early to say.

No, I think PS5 will sell more than 70m units.

The PS5 will likely sell less than the PS4 lifetime, and by default less than Switch. The XBox brand has a good chance to get some of the market share they lost with the XSX/S, and they are making a lot of good choices in that regard. While I do not think it will outsell the PS5 overall, it will cut into potential overall sales.

The Switch on the otherhand will continue to sell like wildfire, as it is a good supplement to either console. Couple that with the people that main the Switch due to portability, and it will remain ahead of the PS5 relatively easy.

Cliff™

Nintendo consoles have much better sales dynamics but Sony has better longevity