my screen goes black after 30 seconds of inactivity in Ubuntu 22.04

My screen goes black after 30 seconds of inactivity and when I press a key, it shows where it was and does not need any password. This problem won't occur when I use it for watching videos in platforms such as youtube etc. My Ubuntu version is 22.04.I have used some methods to overcome it but still couldn't.

1. I've changed screen blank to "never" in setting>power>screenBlank
2. I've used commands such as 'gsettings set org.gnome.settings-daemon.plugins.power idle-dim false', and 'gsettings set org.gnome.desktop.screensaver lock-delay 600' with and without sudo in terminal.I restarted my pc after them just in case.could you please help me with this?