The absolute best I’ve seen is qwiklabs which provides hands on learning for GCP and AWS. I say its the best because they give you credits and a “sandbox account” for their lessons. So if you wanted to spin up a massive Kubernetes cluster you can without worrying about the costs related to such stuff.
This way you can full on hands on learning using the actual cloud, rather then just following some document, and worrying about making sure you delete everything after so you don’t get charged.
Along with this, qwiklabs is owned by Google, so it has more or less first party support for GCP. (I guess they go over AWS aswell from the looks of it too)
Unlike most of what I link in FCC this is not free, nor is it very cheap. (qwiklab pricing, 1 credit = 1 dollar) But you get what you pay for in terms of quality of the lesson and ability to actually “do stuff”.
Otherwise if your cheap (like me), following the cloud provider youtube channels is an easy way to get easy to consume, high quality first party content directly for free. You wont learn much more then a high level overview, but its a great way to at least get an idea of the content.
After the official youtube channel’s, watching videos from conferences where people use the cloud to do different things is another easy to consume, and usually more detailed oriented overview of a given technology.
Finally if your done watching someone do stuff, following the official docs usually goes over some kind of “getting started” setup and should give you enough to at least get going most of the time.
I personally don’t recommend paying for lessons since its easy for stuff to get outdated, or get overpriced for something you could get more or less for free from the cloud provider itself. Not much beats the official docs, even if they usually feel like they are missing the details, they are usually the best anyone has. Plus, the cloud provider wants the documentation to be easy to use, as they want you to use their cloud, so there is an incentive for quality.
PS. I use Google Cloud for work, and my own personal projects purely on familiarity. All three major clouds are similar in terms of offerings, and each has their strong points, but generally can provide the same quality for most use-cases. AWS is the largest, so it is usually the most talked about and popular. It could be said its the most popular for no other reason then its the largest though haha.