I would use Chrome for iOS as I prefer its UI, but Apple doesn’t allow content blocking in non-Safari browsers so you must use Safari too.
It’s really the last vestiges of iOS’ immaturity. As Apple is clearly pushing iPad as a primary device now, I have hope they’ll remove all the various restrictions except the ability to install apps outside of the appstore. They’ll never, ever, back off on that.
Outlook on iOS is a surprisingly great product. I use it for work email, with Airmail for private accounts. The only Apple apps I use regularly are Safari, iMessage, and Facetime. And like I said, I would prefer not to use Safari but have no choice in the matter.