Zoom ppt Video - "WindowServer” Process slowing machine down HARD

Welcome, Haghiris, to Apple Support Communities!

The «process called “WindowServer”» is a normal macOS process that takes care of the windowing Graphical User Interface (GUI) of your system: it will involve a fair amount of processing when you are doing a lot of GUI processing. It will take memory to keep track of its work, in behalf of your running Applications.

As for your Random Access Memory (RAM), this is used as needed for the active processes on your system: it should usually run at 100% used (including file cache). If not, you have wasted your money on buying more RAM than you need. (Your system has 16 GB, which should be just fine, in most cases.)

As HWTech has pointed out, the worst thing you are running is CleanMyMac.

In addition, you are running quite a few system/kernel extensions.

While your are running macOS Big Sur 11.2.3 (20D91), yet you have a fair amount of older software, that predate Big Sur: these are highly likely to be incompatible with this major Operating System (OS) upgrade.

Such should be checked for compatibility with Big Sur, using the check your applications for compatibility resource, or by contacting the manufacturers.

Uninstall CleanMyMac by following the developer's instructions. Anti-virus apps, cleaning apps, and third party security software are not needed on a Mac and usually causes more problems than they solve plus they impact system performance. If you still have issues after fully uninstalling CMM, then run EtreCheck again and post the new report.