Although I agree with the sentiment of voting with your wallet, but building the foundation of my GPU workstation that could cost me a lot in electricity if a bad actor took control of it on pirated software is ill advised.
You can download official ISOs of all of the Windows versions for free directly from Microsoft's servers. Then you just need to activate it and there are plenty of methods to do that without risk of malware. Microsoft seems to care about this so little that one of the most starred repositories in github(MAS) has provided easy one click activation solution for years at this point.