CAD programs, e.g. SolidWorks, Alibre, SketchUp, eDrawings, Fusion 360? Windows.
CAM programs, e.g. BobCAM, MeshCAM, MasterCAM? Windows.
Office? Windows (LibreOffice is not a functional replacement - you can’t risk having documents being sent to clients looking bad).
FileMaker, Act! Pro, other desktop databases? Windows.
Router control software, e.g. Mach3, Mach4, UCCNC? Windows.
Adobe anything (GIMP is worse than a joke)? Or, if you don’t like Adobe, Affinity? Windows.
No shortage of Windows and Mac only programs in a business. Other than MasterCAM, my family uses or has used every piece of software I just listed in our small business. Linux is not an option; only for home hobbyist use, maybe. If you could get by with a Chromebook, Linux will work for you, otherwise it probably won’t. (This might sound like a slam, but remember Steam also runs on Chromebooks now.)