I put my hands on a Chromebook for the first time today and I felt that it was not that bad.
There are a lot of privacy toggles to turn off, you can create a Google account without personal information (fake name, …) and avoid using their apps (photos, Gemini, NotebookLM, keep, …).
You can use alternatives (brave, ente, Proton, …) and conmect to a VPN that blocks (some?) telemetry.
You can also turn off synchronization to your Google account or select what you want to be synced (apps, settings, networks, wallpapers).
You can delete most Google apps except Chrome (but you can change the default browser), and even log out of Google Drive (with the computer still logged in your main Google account).
For file synchronization/backups, you can use Cryptomator (paid) in conjunction with an unencrypted drive solution (Google Drive, Dropbox, kDrive…), or use a third party drive solution (Proton,…) that integrates in the files app like on Android.
And I feel that you keep some of the openness of Linux/Android because you can still sideload Android and Linux apps easily. The Linux environment is surprisingly very easy to setup (btw this was in fact my first contact with Linux desktop).
They are very cheap and I feel that apps open much faster and I like that there are 10 years of updates. I will consider one when my Macbook stops receiving updates. (If ChromeOS still exists lol, Idk what will happen with the rumors of Android desktop and the teams of ChromeOS and Android fusionning).