High memory/ram usage with no heavy apps running?

Hello everyone. I was using a 8gb ram m1 mac mini and the normal ram usage was about half of the total ram(4-5gb). I upgraded to a 16gb ram version and noticed that without having any apps open, it is consuming about 9-10gb. Before I switch to mac mini I had a iMac 27 2017 I upgraded the memory to 40gb and it was a similar issue, without any apps open it was using about 20gb alone. What cause this situation? Thank you