Microsoft allows Windows 11 to be installed on older, unsupported hardware but specifically nixes official support — minimum requirements for full compatibility remain unchanged
When installing on unsupported hardware, Microsoft will push a small disclaimer that effectively cancels your warranty in case of compatibility-related mishaps.
In case you didn't know, your Windows license allows you to contact Microsoft directly for support if you are having issues. (Just be sure its an actual Windows issue and not a software/hardware issue)
This will effectively end that support for your device.
The only thing I can see this affecting is the Secure-boot requirement.
Which is very odd to consider that anything compatibility related would likely have nothing to do with secure boot, and everything to do with Windows being Windows.
So, most windows installations come with an OEM key because it came pre-installed. OEM keys, last I knew, don't have this support, because the manufacturer is responsible for that.
If you bought a lenovo laptop, its on lenovo.
But anyone has been able to buy windows directly with a standard license key and windows supports those computers directly. I've never bothered to use it but I worked with people who did and (again, last I knew, some 10+ years ago) they got someone with a thick accent reading from some support article who didn't know what they were about.