I would highly recommend this as I did something similar. I ran Linux on an older machine separate from my main machine. I did so for about 10 months. Plus I built out a gaming machine for somebody and set up another old machine as a media center, both with Linux.
I finally made the 100% switch just a few months ago. I bought a new M.2 drive and swapped out just like you are planning. I really needed to make sure I had no hitches for work purposes. I haven’t even considered swapping back (though in full transparency I have Windows running on a VM for some apps that I can’t get in Linux)
It hurts to even read that. I can’t even imagine your frustration.