While your frustration is understandable, you aren't really providing much information that the people here can use to help you - for example, you are on a 13" MBP running Sonoma according to your profile tag, so the likelihood that the cryptographic sealed System volume that is mounted at /System has ballooned to a ridiculous size is...well kind of ridiculous. Files in /Library, including un-emptied trash and snapshots...maybe...but most of the people are shooting in the dark trying to give you things to try.
You say you've scanned the drive and 9/10 are "system files"...cool...scanned with what? What directories or mount points are these files in and what are the largest files? This is the sort of info that would help the community try to narrow down on your problem and how it might be addressed.
If they are missing the point, it's partially because you are obfuscating the point from them.