In his Keynote address at //Build2018 Scott Guthrie said that the pace of change can make adoption of cloud technologies intimidating and difficult.
Microsoft are going a long way to fix this by increasing the quality of the documentation, creating free training content on Pluralsight and publishing comprehensive training plans on the learning website.
It is no longer realistic to be an expert in all areas of Azure, or AWS or Google Cloud. It’s OK to be a specialist.
Pick one or two areas that interest you and deep dive. During that deep dive you will likely learn supplementary information about a whole load of other topics and areas. Remember you don’t need to know them all. My particular interests lie with websites and IoT.
Luckily there is a whole lot to learn in both those areas. Dive, dive, dive!