How to speed up load time in and out of your app

My question > > Also, regarding the storing of data on their phone in-app instead of via server, can you please clarify what is now stored in-app? We think it is all shop data including addresses, pics, reviews etc. Also all of a person’s own posts so their profile page loads quickly. Re: Inspo, Treasure and My Circle posts, does the app retain all posts already downloaded into the phone, then just update them whenever the app is opened, but drops off older ones as new ones are added (ie we set the number of each it retains on their phone in-app, and if for example 3 new treasure posts come in, 3 old ones are dropped out of storage?). Facebook seems to do something similar to this. Just want to understand how it all works.

App developers answer >>> > We are not storing any data on users’ phones. Although, the user’s info does store as a cache on their app. The data is totally dependent on the server. Once the app opens, the whole data including posts, etc downloads from the server itself but there is certainly a cache system that keeps their data within the app on their phones for a few days. If you prefer, we can switch from Firebase to AWS to make the processor of the app a little faster but it’ll be way more expensive. Uploading on AWS is superfast, much faster than Firebase. The download is pretty much the same as they both compress data on their server and only downloads when you open the app…

Does sound correct??

Is there answer