4.3
Are there any way to decrease size of the app? I fear it may be deterrent for players to download it when they see the size, also why the 54 mb increase? Before it was non -gradle and non admob plugin build. Dunno which one affected more.
No, find a different ad plugin. Or make sure you are using a release version of the plugin and export.
Do you really believe a plugin can increase size of 54 mb?.. 
“Compress native libraries” checkbox did the trick.
yes, and easily
If for android game, it can “easily” increase as you said even with “compress”, developer(s) just should think about alternative solution^^.
Yep, write only the necessary code instead using convenient, general purpose, libraries and plugins.
For comparison a Monument Valley 2 is 300MB. Your assets will probably really bloat the size.
Among us - 469MB
Many popular games are around 100 - 300MB, i wouldn’t worry about the size and more about how fun the game is, especially this day and age.