The "Top Processes Snapshot by CPU" section does indicate "Other processes" as the culprit, but as you can see EtreCheck was unable to determine what it is.
The good news is that there were no kernel panics or any significant diagnostics reports. FYI, the WindowServer is a core macOS process that can be thought of as a liaison between an app and the device's display.
The only thing that comes to mind is that Google Chrome is a resource hog. I would suggest completely removing it and go back to using Safari. If you just can't "live without" Chrome, may I suggest that you try Opera which is also built on the Chromium engine and is very similar to Chrome.
Another option, is to create a new user account. Log out of your existing account, and then, log back in with this new account. Try using your notebook for a few days to see if this resolves the issue. If it does, then we know it may be something amiss with your regular account. If not, then maybe a visit to your local Apple Store is in order.