Decent Android device for testing our mobile game

I'm using Unity to work on a children's adventure game for Android (and perhaps iOS eventually). It is kind of like an old school Sierra/LucasArts adventure game but with 3D characters & levels.

I've only owned iPhone/iPad, so for testing I picked up an used Samsung Nexus 10 Tablet https://en.wikipedia.org/wiki/Nexus_10

The problem is that no matter how much we try to optimize (scale down textures, reduce polygons etc.)... I can't get the game running at a decent framerate. It's usually 6 - 10 Frames a second. Scenes are simple and I would say half of the textures have normal map textures, with 2-3 point lights at most per scene. As we optimize that is getting cut down as we speak.

That aside, collogues are telling me that the game runs fantastic for them; a solid 30 FPS on their devices (as it is capped at 30 for some reason). One is using a Samsung S8 and the other a Samsung S9.

I know that it's better to optimize for older hardware, but is my hardware TOO old? Say that we want most kids to be able to play this game on tablet/mobile phone, what device should I be testing on? Any recommendations?

I hope I've supplied enough details, If you need more information let me know. Thanks in advance.

 

Thanks so much for the advice on device logs. I will make sure to check that.