Has Windows startup repair or a troubleshooter ever fixed your issue even once?
Yeah, basically that. I'm back at work in Windows land on a Monday morning, and pondering what sadist at Microsoft included these features. It's not hyperbole to say that the startup repair, and the troubleshooters in settings, have never fixed an issue I've encountered with Windows. Not even once. Is this typical?
ETA: I've learned from reading the responses that the Windows troubleshooters primarily look for missing or broken drivers, and sometimes fix things just by restarting a service, so they're useful if you have troublesome hardware.
I've occasionally had success restoring a network connection with troubleshooter. Generally if you switch between Ethernet and WiFi, Windows will get confused, but the troubleshooter will turn the network devices off and on which gets it back. I find it's easier to turn off the device I'm not using, but if that's too complicated for someone usually "run the troubleshooter" works.