I expect that the user experience and security are better on ChromeOS. But that depends on who you're trying to secure against. I'm not particularly worried about state-level actors or even garden-variety malware. But I am worried about surveillance capitalism, and that's what Google has built its business around. So I would not trust ChromeOS to be secure against Google.

(Having said that, I still haven't been able to completely wean myself off Google services, so Google already has plenty of data on me, and gathers more every day.)