Hello.

I have Samsung S22 and Android 14, OneUI 6.1

I downloaded app from the web. But it seems to me it runs only when the screen is on or Screen Curtain mode applied.

I tried to add to Never Sleeping Apps, but the app is not appearing in the list.

What should I do to make it run everytime in background (assuming other constraints are valid: charging and battery level above my threshold)?

Which version of Android BOINC did you install?

If it's one of the more recent ones from version 7.xx... and later...
Open the BOINC APP then ...
Open the menu in BOINC by tapping the "hamburger" menu button in top left corner.

Scroll down to the Preferences gear icon. Tap on it. A new menu appears.

Scroll down to Show advanced preferences and controls. Make sure the box to the right is checked.
If not, tap the box a check mark should now be visible in the box.

Right below is the preference Pause computation while screen is on. The check box to right should be blank/unchecked.
If not, tap the box. The check mark should disappear and you should have an empty box.

Press the BOINC menu button again to go back to the tasks list. It could take 5 to 6 minutes for BOINC to resume computation again.

App version: 8.0.3

The issues seem to be related not to the app, but how Android (or Samsung) treats this app.
It's not appearing in this battery optimization menu, therefore no background activity is allowed (or that much background activity).

The rest of the options in the app itself are ok.

I played around with a Samsung SM-T510 tablet a few years ago, and hit the same problem as you: no computation unless the screen was active.

I found I could work round that, by invoking the Android screensaver. That told the relevant bit of the operating system that the screen was on, but it was using very little power, and just displaying a soothing slow swirl of colours

I think it's Android from version 11 and newer. I vaguely remember having to do the steps mentioned below after getting a new phone.

Try this workaround:
Open the Settings tool (gear icon) from your Android screen when you swipe up.

Scroll down to Applications Tap to open. If the BOINC app doesn't appear, tap on Show all (number) apps.

Scroll down to BOINC, tap to open Settings, scroll down to Battery, tap to open. Tap on Unlimited settings in this menu. Close the menu.

This should override the Android settings and allow BOINC to run.