Given your image, Avast's memory use is moderate added together it comes a little over100MB
I also see BraveSoftware Update and the (32 bit entry), which is also low. However if there was a software update in process this could cause a spike in Avast CPU activity and possible memory usage. When RAM is high order the Task Manager by RAM usage and see just what is the highest user.
The biggest culprit for memory usage on my system is my browser Firefox, the more tabs open the more RAM used. I only have 8GB of RAM on this system and it doesn't often get what I would call high 75-80% or higher.
RAM is there to be used, it speeds up your system, by not having to constantly move data out of memory into the pagefile.
How much RAM is on your system ?