The point is that your app is not only your app, it is your app (what you coded) PLUS everything that is implemented behind the scene by Thunkable.
Create an app that does nothing (no components, no logic, just an empty screen1) and it will still be a several megabytes apk file.
Look: it is offline, and it requests permission for bluetooth. If requests permission for reading and writing calendar. It wants to be able to vibrate the phone.
It looks like Thunkable has all those processes pre-loaded, even if you don’t call them.
Yes I understand you now. Well that is kind of annoying. I was testing things out, and it says that before I click download button on play store, I get pop up saying it wants all these permissions. It is a bit of a deterrent.
That is why I am considering enyo ( https://enyojs.com/ ) for eventual cross platform development.
It is based on JavaScript, which implies “regular” coding (as opposed to those drag and drop elements).
That is, unless MIT App Inventor (which is supposed to be released in a mode that supports iOS as well later this summer–don’t hold your breath just yet, however) manages to get acceptable resolution in their canvas.
Developing in JavaScript/HTML/SVG may be a bit more laborious, but will likely produce much more lightweight and much faster codes.