I used to teach computer science to kids, and I had middle school kids setting up their own website with GitHub pages and buying their first personal domain. Firebase is also pretty amateur-friendly (although certainly more bloated than its early days) and I've seen novices deploy real-time apps with authentication, storage, server-side functions, etc.

For professional software work, the dominating reason I favor a decoupled architecture is so I can have a frontend team and a backend team. I want the frameworks and existing libraries/processes/tools to lean on, so I can minimize how much engineering time is spent on reinventing wheels.