PS4 first
Switch second.
People are underestimating the attraction of great graphics. Also the PS4 is cheap now, and there is still a lot of love for the DQ/Playstation duo, and a lot of love for the series to return to a home console. Also I think the Switch version will run poorly.
I don't know where the 3DS sales will end up though. Because I think DQ is one of those games that will make a lot of people get a new console, and the 3DS version is just ugly AF and outdated. But at the same time the huge installbase of the 3DS and the cheaper price of the game itself will really help this version.