List preinstalled apps with adb shell pm list packages
Uninstall some of them:
adb shell pm uninstall --user 0 com.miui.systemAdSolution
adb shell pm uninstall --user 0 com.miui.analytics
adb shell pm uninstall --user 0 com.android.browser
adb shell pm uninstall --user 0 com.miui.video
adb shell pm uninstall --user 0 com.miui.player
adb shell pm uninstall --user 0 com.xiaomi.gamecenter.sdk.service
adb shell pm uninstall --user 0 com.xiaomi.gamecenter # no permission