Several months back I had to sell my switch and its games to pay for rent. I recently was able to get a new one. Is it possible to get my old data back, or have I wasted 400 hours of my life?
Technically, yes you can. You can log into your account from the new switch. Source
EDIT:
This is right as long as we assume the asker bought a Nintendo Online subscription for their account to access cloud saves. -Gekky
So, if you had online, you can access cloud saves from the account that you have online on.