'Ownership' of Windows isn't the installation, it's the licence that lets you perform the installation.
The exact terms of what MS let you do with a copy of Windows are, well, not always clear. For instance, the free upgrade from Windows 7 or 8 to Windows 10 was, according to MS, only for 1 year after Windows 10 came out. But people have been upgrading for free well into 2020. MS's activation servers still allowed it, and it was widely publicised by (legit) PC websites.
As long as you are only using the licence on one system, you may be able to transfer it, e.g. by linking it to your MS account.
In general, it's
not been allowed to do that with OEM licences. Which is the kind of licence you almost certainly have for Windows on your current laptop.
Deactivate your old PC instead of buying a new license.
www.howtogeek.com
However, it's possible MS may allow you to tie the licence to your Microsoft account and transfer it that way:
This guide shows you the steps to reactivate Windows 10 after a significant hardware change, such as when you replace a motherboard, hard drive, or processor.
www.windowscentral.com
I don't have an OEM key to try it, so that may not be something they allow.