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.