To be fair, requiring a Google Account alone isn't lock-in; lock-in would be if the OS forces you to use Google cloud services for a bunch of essential tasks, which could then make it hard to migrate to another platform.

I'll admit that I don't know for a fact that it does require this, but I just kinda assumed it might. IIRC you can run Android apps on ChromeOS, and if you buy apps from the Play store, then you're stuck with ChromeOS if you want to continue to run them. Otherwise you lose that money you paid.