Unable to activate Windows after reinstall

Somehow my Windows 11 Home got corrupted, so I had to reinstall it. I have the USB that I purchased when I built my PC, so I used that. I didn't save the activation key.

Since Windows was already activated prior to the reinstall, my understanding is that the system is supposed to automatically reactivate after the reinstall.

In my activation settings, it says not active and it gives me a message about not having a valid license. (Error code: 0x803FA067). If I hit Troubleshoot, it just says troubleshoot has completed and it wasn't able to activate. If I click "I changed hardware on this device recently," it opens another dialogue which also fails and just says "Unable to activate Windows." From here, if I hit "See other devices linked to your Microsoft account" it just says "We can't reactivate Windows from these devices."

I really want to avoid paying $130 just to get rid of a watermark when I already paid for a valid license previously. What else can I do?