There's nothing much we can do about app vs. browser performance - the performance is determined by the Android System Webview, so this would be something to report directly to Google.
As far as we know Android apps run fine in the majority of cases, but this might be related to WebGL 2 issues on Mali GPUs (but hard to tell because nobody's mentioned which Construct 3 version they are using... this is why we need comprehensive details in every case...) or possibly a reappearance of this issue (hard to tell due to lack of diagnostics in the webview). Maybe you could connect USB debugging and see if there are any logs in the console? The C3 runtime should log warnings if there is an obvious performance problem.