In my opinion, since you bought the Windows 11 license, you have the right to install it in any device you can, even your microwave! How to accomplish this is your problem. Microsoft just tries to discourage you installing on unsupported devices, but doesn't stop you entirely. In comparison you cannot install Mac OS on non-Apple computers without some elaborate hacking and modified installation media. Don't forget that Windows 11 can be activated with a Windows 10 and probably also Windows 8 and 8.1 and 7 key. So if you activate Windows 11 on the netbooks using a genuine Windows 7 license and give the sticker with them, it should not be illegal to sell them. Just make it clear to the buyer there will be no official support from Microsoft and he should ask for your help. As for graphics drivers, you can download the Windows 10 one from Microsoft Update Catalog and manually install it from Device Manager.