Hi,
I happen to have the same question.
I think the answer is here: Google Data Safety page-2#post-8280975
The Unity representative commented: "You have no services enabled so nothing is being sent. And therefore nothing is being stored. We don’t send any secret data that I am purposely not telling you about. The “might” and “may” refer to services, specifically custom events with the Analytics service. The “might” and “may” refer to you, the developer, who may be sending custom events or other explicit events. "
They also recommend double-checking it with Charles Proxy (https://support.unity.com/hc/en-us/articles/115002917683-Using-Charles-Proxy-with-Unity). They say if it does not show any data sent to unity3d.com then there is no data collected.
I still have some reservations. That thread is 1.5 years old and something could have changed since. Also if the Charles proxy does not show data sent to unity3d.com it does not mean the game nether sends the data, maybe it does send the data on some rare occations.
Did you manage to find an answer somewhere else? Did you have any troubles in Play Store or App store by declaring there is no data collected?