Track the number of events unique to the user, not the session

We have a way to get the number of sessions that is unique for each device and the number of uses of the new feature, this can be done using a public API and requires two events to be executed, which will be sent by mobile apps to the Google Analytics server. It will give us session statistics when the new feature was used, although this does not directly reflect the activity of individual users.

Ex: the application was opened 1000 times among all unique users (devices), the new function was opened 200 times, the total value is 200/1000 or 20%. The disadvantage is that in this particular case, we cannot say that it is not the same user who opened the "New feature" 199 times, and another who opened it only once, the real retention rate is negligible.

The secondary statistic we want to calculate is the percentage of unique users who have used the New Feature at least N times in a given period. This statistic should be a closer representation of the actual retention of the new feature, as it will show the proportion of users who used the feature and the dynamics of the frequency. For this, it is not clear to us what events are required for the configuration.

Ex: the app was opened 1000 times: user A used the new feature 10 times, user B 5 times, user C 4 times, most of the other users who used The New Feature opened it 2 times - the new feature was opened only 200 times. The resulting percentage of users: 10% have opened a new function at least once, 8% have used it at least 2 times, ..., 1% have used it at least 10 times.

The numbers in the second example give us more useful information about how often the new feature is used, but it's not clear how we can customize it. We need some kind of event that shows that the use of the new features is unique to users (not just sessions) and I think the event values ​​can be used to distinguish between users, if it would be possible to get the number of unique users that raised the event like at least N times in this way? Any other suggestion is greatly appreciated.