Just get a dedicated Windows computer that runs nothing but that one piece of software. When you have specialized tools and software, you have to think of the computer as a part of that package.
If you’re heavily invested in the Apple ecosystem, and your productivity is really good with macOS, then you’ll just need to have two devices. Maybe you can get by with a 15 inch MacBook Air, if the windows machine is doing most of the heavy lifting. Or maybe not, maybe you’ll just have to have a Windows laptop and a MacBook Pro that you carry around in your truck.
Having two devices, each dedicated for the job they do, seems like the best option. Trying to force software to work on something it’s not designed for, or getting frustrated trying to use windows with your daily tasks, does it not make sense. In short, just plan on using two devices. It doesn’t make sense to force everything onto one.
(any chance you can just skip the Windows machine, use your 2019 MacBook Pro for the special application, and then use your M3 Max for everything else?)