Did you check out the second link I gave to stop windows 11 from closing avast when you go into sleep mode ?
As if avast is effectively restarting it is going to be using more ram/cpu resources when it starts as it is going to be scanning all running programs, checking for program/VPS 9Virus Pattern Signatures) updates. That should reduce later.
This image is for my win10 installation of Avast Antivirus Free, very light.
