Sure, the closer your config is from the actual user config the fewer issues you'll get, but I wanted to highlight that even with electron you ought to test on different configurations.
Oh, yeah, certainly. Even when I've made dinky little Electron apps I've had a Windows machine ready (I otherwise use Linux and macOS) just to make the Windows binary and do some rudimentary acceptance tests. You can't get away from testing on all your officially supported configurations.