I think this question is a much bigger than it seems at first. I made a streaming website a while ago, depending on how non-technical you are I open sourced it if you want to browse, it's not well documented, but it should give you a sense of all the pieces needed https://github.com/MichaelEstes/Scrim-TV I used Go as the backend because I knew it well, but you're also going to need a few databases and a CDN. It's a lot of moving parts without a black and white answer.

Depending on how non-technical you are, I'd focus more on finding the services that meet your product needs for the best price. Moving to a new backend is a lot easier than moving to a new cloud service provider in my experience. There's only a handful of them out there so once you have that it won't be hard to find a shop that has a great deal of experience in it and they'll use the backend they have the most experience in.