You can use https://uupdump.net/ to build up an ISO file (even from Linux or Mac, the options enable you to keep the file size down) and just drop into https://github.com/ventoy/Ventoy and you're good to go.
If you're already running Windows you can do ⊞ Win
, Reset this PC
for a more convenient ISO download option.
For keys try https://www.microsoft.com/windows/get-windows-11 or local retail store, otherwise check PC Hardware channels on YouTube as they often have links to discounted keys (obviously check if valid/legit, due diligence, etc.)