Reproduction steps:
1. Create a new Unity project
2. In Build Settings, click Export project
3. Incorporate it into a Native Android application (Unity as a Library) according to Unity’s official Github tutorial
4. Set the flag: {{getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);}} in the OnCreate or OnStart method of the MainActivity.java
5. Ensure to set your Android device screen timeout to the lowest (e.g 15secs)
6. Build and Run on Android
7. On the app select either “Show Unity" or "Show UnityGameActivity”
8. Observe the app’s screen for more than 15secs ( or the amount of screen timeout you used)

Expected result: The screen remains on
Actual result: The screen turns off after a couple of seconds depending on the screen timeout on the device

Reproducible with: 2021.3.33f1, 2022.3.15f1, 2023.2.4f1, 2023.3.0a19

Reproducible with these devices:
VLNQA00518 - Google Pixel 4 (Pixel 4), CPU: Snapdragon 855 SM8150, GPU: Adreno 640, OS: 12
VLNQA00414 - Galaxy Note10+ 5G (SM-N976V), CPU: Snapdragon 855 SM8150, GPU: Adreno 640, OS: 9 VLNQA00278 - Xiaomi Redmi Note 7 (Redmi Note 7), CPU: Snapdragon 660, GPU: Adreno 512, OS: 9.0.0
VLNQA00139 - Vivo Xplay6 (vivo Xplay6), CPU: Snapdragon 820 MSM8996, GPU: Adreno 530, OS: 7.1.1
VLNQA00132 - Xiaomi Mi 5s (MI 5s), CPU: Snapdragon 820 MSM8996, GPU: Adreno 530, OS: 6.0.1

Testing environment: macOS(Intel) 14.0 Sonoma, Android Studio Flamingo | 2022.2.1 Patch 1

Notes: If you stay on the Native app screen(i.e the one that show ups when the app is launched) the app obeys the set flag but as soon as you move to a Unity scene the flag is overridden.
This could be as a result of code found in UnityPlayer.class:

{noformat}private void hideStatusBar() {
Activity var1;
if ((var1 = this.mActivity) != null) {
var1.getWindow().setFlags(1024, 1024);
}
}{noformat}