Support devices Android

Hello everyone I’m packing a project for Android on the 4.25.1 version engine. When publishing the build in Google play, you will see that the API level is 21+, and the target level is 28, which is why only 3.6 K of the 16.5 K devices support the app. If you set the target level of 21, then Google will swear that you need a minimum of 28. Do I understand correctly that it is now impossible to increase the number of supported devices, or is there some way to do this?