I've also used a Nexus 5X, so I have some experience with it.
I've been an iPhone user for the last 3 years. I've bought an iPhone 5 a couple of years ago pretty cheaply because somebody else payed half of it. I had been using that phone for 3 years, but then it started to act up (mostly battery issues).
So I got rid of it and was reluctant to shell out 860 euro for a new iPhone 6s. (read: I couldn't justify it to the household budget ) So I was like: "heck, those Android phones probably aren't that bad also, after all, more than half the planet uses them". So I bought a OnePlus X. This phone worked fine for 6 weeks, but then the WiFi started to act up. It would connect, but no data would get transferred. This obligated me to use my 4G connection all the time. I tried everything: factory reset, forums, and eventually even sent it back to OnePlus. It returned a few days later with the tech report, saying "nothing was wrong with the phone". So I then decided to get rid of it.

Still reluctant to shell out the cash for that new iPhone, I then bought the Nexus 5X. (which was 100 euro more expensive than the OnePlus X, but still only half of what I would pay for a 6s)
I must say: I really liked this phone. I just found it a tad too big. I didn't get any of the issues that you had, though. And I was thoroughly surprised when I learned about the Google backup feature, that was able to completely reinstall the 5X with the apps that I used on my OnePlus X. Still not a good as the iPhone backup though, but acceptable.

But after 3 weeks of nagging my wife that I still found the screen too big, she told me : "then get that damn iPhone!"

She didn't have to tell me twice.

Two hours later I held a shiny new iPhone 6s in my hand. I've been happy as a kid ever since. The backup utility of iTunes neatly put my last image back onto the new iPhone 6s, and walla: everything was back, up to my texts that ended the day I stopped using my iPhone.

This time I'm here to stay, I don't care what happens. An iPhone is expensive, yes. But it simply works, all the time, every time. There's a lot to be said for that. I am happy that I've at least tried Android though. To be honest: it wasn't half bad. I would even call it pretty good, but it's just not as stable as an iPhone. And I've come to an age where things have to "just work". The days I could get some gratification of spending hours and hours troubleshooting some problem and then finally, at 4 AM in the morning finding the solution are long gone. I've got a family now, and a life. My time have become too precious.