I built my entire flight sim setup around Linux, X-Plane 12 has a native Linux version and all my hardware works flawlessly. MSFS2020 also works through Wine/Proton. But you can always create a Windows VM with GPU and SSD passthrough, (you can also pass through other PCIe and USB devices) and use that for your Windows-specific tasks. I use that for online games that require Windows-exclusive anti cheat solutions.
What are your needs, if I may ask?
Specific flight simulator hardware and specific audio/video hardware and software
I built my entire flight sim setup around Linux, X-Plane 12 has a native Linux version and all my hardware works flawlessly. MSFS2020 also works through Wine/Proton. But you can always create a Windows VM with GPU and SSD passthrough, (you can also pass through other PCIe and USB devices) and use that for your Windows-specific tasks. I use that for online games that require Windows-exclusive anti cheat solutions.
If you have windows in a VM do you need a license key
Nah, just use massgrave.dev