Every time we have needed assistance, Oracle Cloud Platform has offered it reliably and in a timely manner. I am content with their customer support and believe they are among the companies that, despite their high number of clients, will pay attention to everyone. My company is not an enterprise - we are a smaller organization - but the technical support provided by Oracle has been just the same, as they do not prioritize their clients by size. The platform runs pretty much without fault, although we have needed assistance a couple of times. On those rare occasions, we were given their full attention and guidance.
The customer support of Oracle Cloud Platform is reliable; they have answered our questions and proven useful in the past. However, I have my concerns about the technical support. In the past, we have contacted them for several issues and their reactions could be improved; they are prompt, but not always very helpful. We have asked their support to troubleshoot certain features for us and we did not receive the results we expected. For general questions, they will answer quickly, but if you need technical help, you may need to go through a more lengthy process of explanations back and forth. This slows down work and needs to be fixed.
In my experience, if a product offers you courses, it is best to attend them if you can. The same goes for Oracle, as I and my colleagues have attended several courses related to our field of work with this solution. Sure, you can operate Oracle Cloud Platform without these courses. But what Oracle University offers is high-quality training which ends with a valuable certification. You not only can use it to prove that you are an Oracle expert, but you also actually gain knowledge that you may need years outside of those courses to attain. It is not mandatory to go to Oracle University, but it would make your work with the solution many times easier.
I have attended courses for Oracle Cloud Platform, and I think while they are worth it, they are not necessary for everyone. If you are curious, start with the free tutorials they offer; from there you can get an idea if these courses are for you or not. In general, they are just good for your resume, and may even get you a higher salary in some companies. But do you need them to work well with the solution? Not really; you can get this information from the product documentation or online tutorials and blog posts. Oracle University gives you all of it in one place - that is the best thing about it. But you can totally skip it and still work well with the product if you study it well enough on your own.