Safe App to Clean Mac System Files?

senior contributor neuroanatomist wrote a very nice discussion of how to fix this issue, including some suggested utilities that can help YOU identify what big things are clogging your storage. These utilities do NO removal, only identification.

How to free up ‘System Data’ and other st… - Apple Community

As others have emphasized, THERE IS NO AUTOMATIC WAY to reduce this use of Storage, and the Apps that claim to do so such CleanMyMac are absolute JUNK, can be damaging to your Mac, and should NEVER be installed on your Mac.

If you mean anything in the System folder, you can't remove, add of modify anything within. Period.

As far as hidden files and folders, being Unix underneath, there are thousands of them. Hidden for a reason, like the user going nuts and deleting things without knowing what they're for and making your Mac un-bootable.

before you can make progress on this issue, you need to know what are the top items consuming your storage:

I continue to recommend using one either:

• System Settings > General > Storage

• one of the third-party utilities mentioned in neuroanatomist article

Once you have discovered what and where the biggest files are, then (and only then) can you take steps to solve the problem. Any other way is just blindly stabbing at the problem, and unlikely to achieve any meaningful results.

May I suggest that you take a step back and explain your desire to do what you propose doing. You may be laboring under a misconception — the result of utter lies promulgated by companies that seek to profit by selling either worthless or destructive products.

Excerpted from Effective defenses against malware and other threats - Apple Community:

Never install any product that claims to "clean up", "speed up", "optimize", "boost" or "accelerate" your Mac; to "wash" it, "tune" it, or to make it "shiny". Those claims are absurd.

• Such products are very aggressively marketed. They are all scams.
• They generally operate on the flawed premise that a Mac accumulates "junk" that needs to be routinely "cleaned out" for optimum performance.
• Trial versions of those programs are successful because they provide the instant gratification of greater free disk space.
• That increased space is the result of irreversible destruction of files, programs, or operating system components normally protected from inadvertent alteration or deletion. The eventual result will be unreliable operation, poor performance and random crashes that may not become evident for months or even years after their use, when updates to programs or macOS are eventually released.
• ...

Rule 1 of Macs is don't install junk. If you want to remove items you don't need, refer to the Apple Support document I referenced earlier. Use the Finder to do that, and don't do anything without a backup.

⛔️ Don’t tamper with restricted files you know nothing about! ⚠️

MacOS is the most secure operating system on the market. Privacy is at the very core of all Apple products and services.

I would advise against installing anything that interferes with that.

Don’t be fooled by clever marketing advertisement tactics that rely on fear to sell you a solution to a problem that doesn’t exist.

All the best! 👋🏼😉

Here you go: Optimize storage space on your Mac - Apple Support

There are no "Apple-authorised" applications for this.

There aren't even any Apple-recommended apps for this.

See the good guidance provided by our friend @John Galt.