Almost every linux distro is better on RAM than Windows. That said, application memory management has gotten pretty sloppy over the past decade or so. I boot into MX linux (KDE) on my 16GB RAM laptop, and I am using about 2GB after boot. Once I load my password manager and open my browser (Librewolf with 18 tabs) I am sitting at 5.4GB used.

But! Even when this laptop had only 4GB RAM, it always ran MX fast and never complained about low memory.