Advice before buying Nintendo Switch, please

I really don't have the slightest idea about Nintendo. Should I get a N Switch or is it kind of dying already? Maybe I should wait for future handheld consoles? If I buy one, what type? Is second hand ok?

Thank you!

Edit: I only want it for the NES and SNES catalogue + new retro games or just simple games. No AAA, complex, modern games, except Zelda maybe. For those, I have my PS. Thanks!