The other thing to consider is this was an underpowered machine from the GPU side. It would still not be expensive to get a machine that outperformed. Say you went crazy and spent half as much as an iMac Pro you would get a screamer, particulalry if you are using Adobe or Blackmagic software as well as FCPX. If you were not using FCPX, I wouldn’t bother with Mac OS and just run a win box. Even easier to install and setup.
And with a Win box, as Shane says, don’t let it update. Mine stay off the internet until I need to do some updates or register software, then they are disconnect from the internet but not ethernet. Rest of the time a Linux laptop is my front end to the internet. Apart from the cost savings of build your own, I also keep power supplies and all monitors, keyboard, mouse etc. The iMacs are a very wasteful design that requires junking perfectly good components just to do incremental upgrading. My monitors are now nine years old. Mouse and keyboard older. Power supply is six. All perfectly working. Cut down on ewaste.