Keep the PC in low power, but not sleeping, disable sleep, disable suspend, disable lid close, disable monitor sleep

I am trying to use my old notebook to monitor some things, and I really don't need it to run past its lowest frequency, since it will only gather data every few minutes or so and relay it. But the problem is, I don't want it to sleep either. I am using pm-powersave true but after installing it, suddenly the PC sleeps very often and the ping only replied a few seconds after I press the button at the notebook. I've tried with cable and wifi. The OS is Ubuntu Server 23.04, running on an old Compaq Presario with Core Duo processor. Is there a way to prevent this? What is the correct way to keep it at minimum frequency but stays awake?