There are a couple parts to it.
As someone who's been in the industry a long time I think Azure and AWS are very easy to use compared to the bad old days where you would call/send an email/create a ticket and wait for somebody else to provision a machine for you, add a disk drive or something and it was like Russian Roulette in that there was a 20% chance they'd so something seriously wrong.
So far as automatability is concern I think people who are struggling are struggling because they use Chef, Puppet, Ansible, CloudFormation and other high-level tools that introduce complexity. It is dead easy to write a Java or Python program that creates a cloud instance and all the resources it needs and writes a bash init script that will configure the machine however you need it. If you try anything else you are always going to be debugging problems that were introduced by your tools.
(I know some people swear by it, and the ability to 'build your own instance' looks cool, but I had some terrible early experience with Google Cloud Computer)
So Vercel partially has an easier UI because it is a simpler product for better and for worse. Azure is "simple" for some people because you can often "lift and shift" an on-premise system in the cloud with a 1-1 mapping of concepts. You can use cloud native services at your own pace.
Now if you start out with Vercel and that's the way you think, it's even simpler, but if you had to move a legacy system there it would be a total rewrite
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Then there's the more superficial aspect of UX which is not superficial at all. It's really a people problem. Somebody on the team has to care about it and the rest of the team has to let them do it. It can be as simple as "there's a person in charge of UX who cares" and management doesn't get in the way. However there are many people on the team with different demands. Sometimes management is in an excessive hurry or is way too niggardly but this tends to be an expensive mistake that can slow down development dramatically. Ideally management believes in the value of good UX and the folks doing the work agree.