Understanding Mobile Packaging

Hi everybody,

I have 2 steps of question,

1st - On my android project simply all supports are on like api 21-28, openGL 2.0+ also vulkan, packaged as multi. I have an android 6.0 also android 8.1 phone so, when i launch the project to the phones directly with cable, engine packaging uploading without problems, project being 243 MB space on android 6.0 and 280 MB space on andrıoid 8.1 and working fine but when i package the project for multi shipping, package becomes with 2.12 GB .obb file also when i try to upload the project from packaged project to my phones this 2 phones becomes, “not supporting device” . Also i tried on another phone that supporting by project it got 2.69GB space on phone. So 2 points here, why project becomes 243MB to 2,69GB and why my phones are not supporting?

2nd - I used this tutorial for android bundle " How To Bundle UE4 Project With Android Studio - YouTube " (sadly i could not find another tutorial to understand android studio much better about unreal to android) bundle becomes 38.5MB and I uploaded to my play console test channel, when I download the game to supported phone, bundle becomes 143MB space on device, starts the game but after few seconds i got message like Xpac file error. So anyone has a better source to understand android studio bundle packaging? coz android studio documentation is not really helping about it.

Regards, thanks