In order to really get good at it you have to work in a mission critical environment that has a real requirement of 100% uptime (Defense Contractor, Military, National Security, Infrastructure, Aerospace, etc.). These types of high profile, cannot fail environments normally have enough funding and range of equipment to run you through the basics to expert (knowing everything connected and not connected on the network in depth, the details of most applications and their quirks, be able to tell what app is doing what by how they talk on the network, keep mission critical stuff up even when multiple racks or data-centers have failed, how to scale without downtime or latency to meet demands and more, creating your own software, os and kernel patches for performance, stability and security reasons, your own network and server gear for special use cases and more).
The good side to working in these environments is that it is normally a mix between AWS, and private highly secure non-public internet connected data-centers around the world and internet connected data-centers.
With time you could go from not knowing a thing to being able to effectively work at an expert level with other top DevOps Engineers in the field around the world in the most demanding of environments. You would be an expert at all the operating systems versions, databases, and modern technology stacks because you would be required to have in depth and broad knowledge to help the broad set of customers that you would be able to encounter. Wonderful thing is they will always have something new to learn that you may have never heard of before.
