Thank you for providing this context and your questions. This deprecation has led to discussions regarding if and how we could support lifetime metrics via the API to replace views with a more meaningful statistic, however these are not available today. This could take the form of an addition to Get Users or perhaps a dedicated channel analytics endpoint as this UserVoice entry suggests. We understand that creators can benefit from multiple use cases provided by third-party developers with this information and will follow up with any features that are added regarding creator analytics.
In the meantime, to your point, other endpoints such as “Get Videos” to sum video views or “Get Broadcaster Subscriptions” with the channel:read:subscriptions scope, might be an alternative to measure creator impressions currently.