This is by far the best and easiest way to upgrade from WIN10 to WIN11 if your Mac does not have TPM
There are two option. Without TPM Option 2 works like a charm. Just perfect! https://www.tomsguide.com/computing/your-unsupported-pc-can-still-run-windows-11-in-2025-heres-how?utm_source=flipboard&utm_content=topic/technology
iMac 24″, macOS 15.3