Haven't read the thread, just replying to the OP -
Rim brake Di2 is a great way to minimise your maintenance. For extra points, a frame with a threaded BB. But if your frame has a sketchy hanger (some are just soft), it'll keep messing up your shifting. Another advantage of Di2 is that you can adjust it on the fly...
There's a good chance the Wheels Manufacturing replacement for your hanger is stiffer; I'd try that.