Yes its one time for android, if you’re earning money with ads or purchases, google will take 1/3 of that amount, then you will have to figure out taxes on your own and there’s also some special policies for selling online goods in India, but if you’re just making apps - its one time fee to be able to upload them to google play store, or you can just distribute with froid/github for free, which is a great route as well
Great core gameplay, multiple boring or just bad patches; devs who care more about their imaginary milsim being close to their imaginary reality than about player fun; slow content rollout (still no new race despite them being leaked many months ago)
In the end I had my fair share of fun but I see no real reason to come back.