Little known fact, if you have windows 7 or 8.1, activate it with Daz loader (win7 only) or KMS activator and then upgrade to windows 10 using ISO you will get digital activation for the motherboard.
Once upgraded then you can even clean install windows 10 anytime on the same hardware (motherboard) and without even asking for a key you will be activated as soon as you go online with that machine.
You can also login to Microsoft account to get that activation linked to your account.
If you wanna try, do remember upgrading from Home will be to Home and Pro/Ultimate to Pro Editions.
Lastly, you can then upgrade win10 to win11 also for free if you want.