No, I didn't get that far. I did some diagnostic testing after talking to another person elsewhere online and long story short, the testing narrowed the culprit down to only possibly being the logic board, so there was no need to get another DC-in board and test it.
My wife's Macbook Pro was running on the latest version it would accept. She was happy with it and just can't justify spending money to get a newer model unless she has a need for it. Her work gives her a top-end Macbook Pro, so she uses that for all her work stuff, and her personal stuff is mostly done on her iPad Pro.
I have a late 2013 Macbook Pro 15", running on 10.14 (Mojave). I could certainly afford to upgrade, but I just get such a hoot out of using something until it's no longer usable, and my current computer does everything I need. I really want to see how far down the road I can get with my current laptop. I always used to say I was shooting for ten years, but now I've re-set my sights at fifteen years.
I agree with you about those 3rd party patchers for getting the current version of MacOS running on outdated/unsupported hardware. Those patchers have been suggested to me a few times before, but I follow the subreddit for the current one and there are so many people in there with crazy hardware/software issues that I just wouldn't have the patience to deal with, not to mention fearing OS updates more so than I already do!