My linux mint 22.2 pc becomes unresponsive if I let it idle for a few hours

Sometimes I need to go somewhere, leave my house for 1 or 2 hours and I leave the pc on cause sometimes I'm working on something. When I come back the pc is still on but the monitor is black and pressing keys don't seem to wake the pc, nothing happens if I use the mouse either, I've to like hold the power button for some seconds and then turn it on again to be able to use the pc.