I actually consider the pager attack to be legal. There's obviously criticism of it, but I'm fairly sure you're allowed to do this kind of thing by laws of war.
Obviously this creates a huge problem for pretty much everyone though, since we can imagine that our ordinary consumer products from all sorts countries could similarly explode if we ended up at war with the manufacturers.
It's not legal, the consensus among human rights organizations and UN experts is that it's a violation of international humanitarian law. But I guess the American urge to see middle eastern people suffer is alive and well.
Expo is a free open source framework that costs absolutely no money to use. You do not need to pay expo any money ever.
Expo Application Services is a set of cloud services that you do not have to use to use Expo. You can set up your own on-prem build infrastructure with fastlane and never use EAS Build. You can self-host your own EAS Updates server. You don't have to use EAS Hosting for web apps. Expo is far less coupled to EAS than Next.js is to Vercel.
Flutter for the web is terrible compared to React Native Web. It's a great way to get your company sued for violating the Americans with Disabilities Act. It literally renders to a canvas almost like the Macromedia Flash apps of old. There's also React Strict Dom now which absolutely blows flutter's web support out of the water while still supporting react native: https://facebook.github.io/react-strict-dom/
I just looked up an example flutter web app and it's completely invisible to the screen reader when I enable VoiceOver: https://flokk.app/#/ . The screen reader literally announces 'web content is empty'. You can't even select text to copy it!
Also, as far as integrations with game engines:
https://github.com/calico-games/react-native-godot
If you want complex 2D graphics like you can do with flutter, react native can also use the Skia rendering engine just like flutter with react-native-skia.