ELK and mobile application analytics

Hi All,
Googled it and confused.
As a back end developer it is huge time for me to decide which data storage can be best for my organisation's analytics related requirement.
So here is the full story.

"I want to do every kind of analytics for my mobile application, which is about IOT based wearable.I have most of the user base information over RDBMS, and the companion app related events are being logged to google cloud;
Ex: which screen user hits it is being logged to google cloud.whatever user activity happens is being tracked back to google cloud.
And for all the analytics ,like who is the user , what screen he is playing on etc, i am querying multiple data storage to track it down, for ex querying RDBMS for user information,for user activity i am querying Big Query to google cloud.
Plus i am showing the analytics data with custom Dashboard designed in HTML +CSS +JS and jquery."

Question is how ELK and other stack of the same can help me to centralise this analytics requirement.

Note : i can reformat my data logging mechanism if it is required.

Please put some light over it.
How effective i can use ELK for this kind of analytics requirement and from where to begin.

Thanks.