Do not download it from the App Store directly (it may give you the "incompatible" error). Instead, use the 'OpenCore Legacy Patcher' app.
This will help in providing a more accurate and helpful response. macos big sur patcher full
This guide delivers all three.
Provides graphics acceleration even for older non-Metal GPUs. Do not download it from the App Store
If your trusty Mac has been left behind by Apple's official compatibility lists, don't rush to the Apple Store just yet. Whether you're rocking a 2012 MacBook Pro or a classic 2010 Mac Pro, you can still enjoy the modern aesthetic and security of macOS Big Sur This guide focuses on OpenCore Legacy Patcher (OCLP) This guide delivers all three
Revive Your Old Mac: The Ultimate Guide to Installing macOS Big Sur
You're looking for a guide on how to use the macOS Big Sur Patcher tool. I'll provide a step-by-step guide, but please be aware that modifying your system software can potentially cause issues, and you should proceed with caution.