Used Xbox games on his own account?

Moin, I wanted to get an XBOX and I wanted to look for a use. But as you know, PC games contain codes in the CD, but you can only use them once. How does it work on an XBOX one S? Can I buy a used game and still play it online on my own account?

Games on disc are not tied to the account. So can you buy used without any problems?

So I can then just normal save the game, and also play online with friends?

If you buy game "CDs" you can easily gamble.
For some games, I think Ghost Recon for the 360 had an "online" code. It was then already used up with me then.
But I have not seen anything like that since then and I do not think that's a general procedure either.
Therefore, you should be able to play everything easily.

Digital of course not. Since I would buy codes only on appropriate secure sites.

Exactly.