Hi Ivan! We do have the possibility in V3 to view all of those metrics.

New users: It's a predefined metric

New User by Country: If you select the new users metric and split by Global Dimension Country you can see new users/country

DAU: If you go to the Explore Tool the default Metric is DAU

Session length, average playtime and retention: These are also in the list of predefined metrics. (session length = playtime per session, average playtime = playtime per user)

You can create a custom dashboard or explore tool views with any of these metrics for easy access.

Let me know if you need help on anything else!