How can I recover data from a lost iPhone and old iTunes backup?

Hey guys, I did have one of my iPhones stolen like 6 years ago, had different Apple id’s ok them. Now I have 2 again and did log in with my old account but now everything I had was backed up. I did have a backup of the iPhone on my iTunes on my laptop . But apparently if it’s another phone I can’t back up . Does anyone know how to get the data from my old account ?

[Re-Titled by Moderator]

Original Title: Getting my data back?