Thanks for your detailed report. Thought there is two different things, the working platform and the set of tools. As long Windows is not open source and not for free, today is actually in the middle way, right? I personally like Windows 10, but the feedback I have from customers is that will work right for some time and than will have some critical issue needing reinstallation, and it is capable to self destruction when you have special hardware and Windows don't know well, it will auto reconfigure and mess with your fine tune - that's a usual complain. On the top (on the bottom really) of all, you have a really old system, insecure etc.. Windows is no good for working, but sometimes is what we got. About the tools, Gimp is not friendly, I know, as most of free open source tools. But I have to say I had more troubles than expected with Adobe apps. The Illustrator environment keep changing and even if for better will take my time to learn how to use it again. The 3D tools are still poor, but Photoshop is still top of the line, specially the capability of working with large files.
At the end of the day, I think worth the try with free tools if the tasks are not too complex or too heavy, I will try.
And if I was you, will work with Linux and a Windows emulated on it, it's easy to backup daily and recover when it crashes.
Finally, I never found a decent backup tool, I still pay for it. Is no good when backup fails! People swear about some free tool working right, it never does to me. Will still paying for backup tools - now working with Carbon Copy.