Resume the app when returning from sleep mode in Android environment

I have a product developed in Android studio.
* Development environment: Android Studio Hedgehog | 2023.1.1 Patch 2
* developed by JAVA
* App usage environment: Android version 10 or higher
* App purpose: Always display a small watermark on the screen (Always stay on top).
And get data from the server every minute and display it on the screen. (Using postDelayed())
I am currently having the following issues and would like to fix them.

Issue:
* There is no problem when the screen is on.
* However, when returning from sleep / deep sleep mode, the watermark disappears and the process is terminated.
(This varies depending on the mobile device, but the problem occurs when using it for about 10 minutes to 4 hours.)

Request
1. The watermark should continue to be displayed (alive / resume) when returning from sleep / deep sleep mode.

Note: never used foreground service (I don’t want ICON is displayed at the status bar)
If you can do this project, I will provide full source to fix this issues.