App not launching in ipad and iPhone
So to summarize, the app ipa is on the iOS device and you need more logs from iOS.
TestFlight is the solution to this sort of problem since it enables telemetry to the developer that you can’t get using iTunes or macOS Finder.
Tell the developer the app doesn’t launch when connected to the internet and to send a new build. Their code signing is being rejected. One reason could be your test device isn’t enrolled for non-production code entitlements. Since you don’t have a Mac, Xcode can’t help you read the specifics from your device. In this case, they should use TestFlight so that you don’t have to mess with these easily preventable failures and make it easier for them to collect failures from your test devices (IMO).

https://developer.apple.com/testflight/