How to delete everything but OS securely?

I'm looking to sell my laptop. I've used stuff like DBAN before but that nukes the whole drive obviously. Is there any good way to leave the OS intact after a reset but also make sure that there's no recoverable data?

Any ideas are appreciated. Thanks!

Edit to add: I don't have the product key for the pre installed Windows 10 OS. Maybe there's a way to recover that and reinstall after a full wipe?