As someone who owns an HTC10 and an iPhone 6S Plus...the keyboard comment in the OP made laugh
I absolutely hate how iOS handles third party keyboards, basically making it a PITA if you don't want to roll with the stock keyboard...but that aside, after installing GBoard today on the 6S+ I am finding myself dealing with the third party keyboard BS as after only a few minutes I find myself loving the experience of typing much more on GBoard...when it comes to corrections it's just as good if not better than the stock iOS keyboard, kinda like Google Keyboard or Fleksy which I've mainly used on Android
Saying you prefer the iOS keyboard is fine, but I do find it a stretch to try and promote that it is somehow better at its job than other keyboards....no, not at all, it's just the keyboard you are most used to because Apple hasn't allowed for third party keyboards until just a year and a half or so ago, and even now that they do the way they are handled basically encourages you to forgo using them because of how clunky it can be.