How To Sync Data From Specific App(s) Across Multiple Devices I know some are going to skip over reading this and just think this is regular Android syncing, I can assure you this isn't the same. I'm not talking about sytem, email, social media, or calender apps. Most normal user apps don't sync data between devices. I'm not developing anything, so this question is posted from the viewpoint of an end user.

What I am trying to figure out

How to sync data from a specific app to all my devices on my home network, without manually entering the data?

(For Reference one of the apps I want to sync data from is ShowBox. There are others, but I would be able to duplicate the solution provided)

Steps I have taken so far is to


contact developer(s)/no luck
write a script/no luck
get an app/no luck
researched/no luck


The answer I'm looking for will be basically non-device specific, but for sticklers at least for Android 4.1 and up. If the answer includes an app or other method, please include details with step-by-step instructions. EDIT Please don't include steps or apps that involve user interaction everytime, because I could manually transfer the data myself just as easy. One last request, it must be done locally. Not online, but do on home network.

EDITED PER REQUEST
In the reference (example) app above, the data I wish to sync would be watched videos and favorites. User data. Like stated above there are other apps I would also use the same solution/steps on.
Also if there is a way to automate the syncing.
Now you're a bit vague when you say data but if I know what you're talking about then I would consider an app called OneNote by Microsoft. 


You need to have a Microsoft account. Go to Outlook and sign up for an email there. You don't have to use that email. It just links all the Microsoft apps together. 
Once you have created the email, download OneNote, both on your computer and all your other devices. Sign in with the email that you have created. 

It will give you plenty of features in which you can sync all your information that you need across all of your devices. For example, I have it on my phone and when I take a picture it is uploaded to OneNote and I can automatically see it on my computer. 

It will also sync all sorts of information and data that you need such as important documents like word Excel and PowerPoint and even video. 


There are also a few other apps that can do the same thing.