WetGeek The OS seems kind of like a browser.
Chrome OS Flex, like Chrome OS, is designed as a "thin client", using online applications and online data storage, both accessed through the Chrome browser. For schools and many businesses, that's a sweet setup.
Installations of Chrome OS and Chrome OS Flex are very simple, consisting of a Linux OS to run the computer and the Chrome browser to do everything else. No overhead or background processes related to anything other than the system and the Chrome browser -- that's why Chrome OS and Chrome OS Flex are fast and run well on low-spec (e.g. Celeron processors, 4 GB RAM, 32 GB eMMC disk) devices.
The Chromebook basic combination -- a basic office suite (Google Docs or Microsoft 365 Web), a solid and reasonably sophisticated browser for e-mail, calendar web access, streaming, online meetings and so on, basic photo viewing/editing, coupled with 5-15 GB online storage -- is enough for many home users, schools and businesses. I ran several political campaigns using Google Chrome, Google Docs, Google Calendar and a few other Google online apps. If I didn't use Steam or installed GOG games like SimCity 3000, a Chromebook would be enough for my personal use today.
Chromebooks 2018 or later can run Android apps and some of the newest Chromebooks can run Linux apps. Convenient but comes at a cost. If you start adding apps to a Chromebook then you need to have more resources (processor, RAM, storage), more processes are running, and so on. If you start doing that, it doesn't take long before you need a mainstream device (i3/15 processor, 8 GB RAM, 128 GB storage). Sooner or later it makes sense to use a traditional laptop running a traditional Windows, macOS or Linux operating system rather than a Chromebook.
Chrome OS Flex, like the original Chrome OS, is basically a browser, doing what modern browsers routinely do. Nothing wrong with that ...