matchboxbananasynergy GrapheneOS will always provide a privacy and security benefit
Just to clarify, sandboxed Google Play does not provide any privacy benefit if you are using an app like Facebook or YouTube. The data collected about your behavior inside the app is the same as it would be on the stock OS. You can limit the visibility the app has into your device and you can deny location settings, but this is not the data they are after anyway.
An alternative front end like LibreTube can help preserve anonymity while streaming YouTube content, but there isn't much you can do about Facebook collecting behavioral data unless you stop using it.