Android game in not working smoothly on Android version less than 10

I packaged an endless running game for android. My game was successfully build and was working good in Android 10 but when I tried it in Android 7, 8 etc. then the game was not working smoothly.
I don’t know much about packaging as this is my first game. Can anyone help me with this?
Thank you.

Most of Android devices which supports 64 bit have either android 10 or more you should not thing of older version as in UE4 the android 10 package does not consist of 32 but armv7a whereas in android 8 you have armv7a support which makes performance difference.

Was it the same phone running different OS, or was it different phones?

Android phones are like graphics cards; an “integrated graphics” will be different from a “GTX 1030 MX” will be different from a “GTX 1080 Ti” on the desktop, and a “Ho Lee Chit $5” phone will be different from a “Pixel 4” or whatever the flagship is at the time.

So, if your testing for older Android versions is using older handsets, it’s very likely the problem is that the hardware can’t keep up with what the engine is doing.