system data

It can be a lot of things, but most commonly when it is that large it is another user account on the Mac.

It won't be in some folder named "System Data." It will be scattered all over the drive.

Use a tool like Grand Perspective or OmniDiskSweeper to find large blocks of data.

I always feel uncomfortable with clean up apps and other software on my mac. I had this same problem. I used the "command + shift + period (.) " to show hidden folders while in finder.

1. Go to hard drive in list view
2. press "command + shift + period (.)"
3. Hidden folders will show up, press "command + J" and click calculate sizes and click default at bottom.
4. investigate where storage is being used. Mine came from a folder labeled "private" and I went down the list and located the largest files. It was a text cache file from chrome that was 94GB. It is safe to delete that file by itself, leave the folders and etc. alone. Cleared up my issue

Sounds like you have trace files enabled. At least on a PC that is disabled. Did you enable it by talking to Kaspersky support?

This discusses it for a PC.

https://community.kaspersky.com/kaspersky-anti-virus-12/kaspersky-eating-disk-space-7346

https://support.kaspersky.com/14550#block1

First, there is no reason to ever install or run any 3rd party "cleaning", "optimizing", "speed-up", anti-virus, VPN or security apps on your Mac.  This user tip describes what you need to know and do in order to protect your Mac: Effective defenses against malware and other threats - Apple Community.  

There are no known viruses, i.e. self propagating, for Macs.  There are, however, adware and malware which require the user to install although unwittingly most of the time thru sneaky links, etc.   

Anti Virus developers try to group all types as viruses into their ad campaigns of fear.  They do a poor job of the detecting and isolating the adware and malware.  Since there are no viruses these apps use up a lot of system resources searching for what is non-existent and adversely affect system and app performance.

There is one app, Malwarebytes, which was developed by a long time contributor to these forums and a highly respected member of the computer security community, that is desshoigned solely to seek out adware and known malware and remove it.  The free version is more than adequate for most users.  

Also, unless you're using a true VPN tunnel, such as between you and your employer, school or bank's servers, they are useless from a privacy standpoint.  Read these two articles: Public VPN's are anything but private and Former Malware Distributor Kape Technologies Now Owns ExpressVPN, CyberGhost, Private Internet Access, Zenmate, and a Collection of VPN “Review” Websites. 

I recommend uninstalling the Kaspersky software according to the developer's instructions. You can check to see if you've removed all of the supporting files by downloading and running the shareware app Find Any File to search for any files with the application's or the developer's name in the file name.  Then do the following search(es): 

1 - Name contains kapersky

Any files that are found can be dragged from the search results window to the Desktop or Trash bin in the Dock for deletion.

FAF can search areas that Spotlight can't like invisible folders, system folders and packages.  

This isn’t an answer but a question for the more knowledgeable group members.

Is it possible that the reported memory leaks associated with Monterey are paging out to disk thus increasing system data?

The group consensus is that ant-virus software is not required on MacOS and as has been shown they mess with your system. Other apps which are not recommended are cleanup apps.