I feel like I'm only scratching the surface of the GamesSparks charts and manage panels. As SOOMLA services are shutting down, and I'm already using GameSparks as backend for my next game, I'm willing to dive deeper and skip the hassle of integrating yet another SDK (like Game Analytics).
For example, how can I get your "Retention % By Day (last 30 days)" graph for 7 or 180 days? For different time periods?
Something like this would be awesome: retention chart
How can I get conversion stats in time? ARPDAU? ARPPU?
I feel like all the necessary data in the analysis collections should be enough to get those things in visual format but I'm still unsure how to do it.
You can do any of these, but you'd need custom management screens for it (and the documentation for this isn't great). I think the best way to go with analytics currently, is to use GameAnalytics or another free analytics service for most stuff, and use GameSparks to fill in the gaps that free analytics services don't cover (such as analytics on user state data).