A number of fake systems have been produced that claim to compress any file as small as you want. They have even been demonstrated! But they all turn out to be a fake system - the common trick is to have a “compression” program that actually just hides the file being compressed somewhere else on a computer, and replaces it with a tiny file. The decompression program copies the hidden file back. It’s a very simple program to write, and looks very impressive because files are replaced with tiny ones, and then reproduced exactly.
You can find a few examples of these if you search for “Pixelon”, “Adam’s platform”, “Near Zero”, or “Madison Priest” (add the terms “compression” and “fraud” if you are searching for these, as there are other legitimate organisations with similar names). Several of these organisations have taken millions of dollars from investors who didn’t understand the limits of compression, and all ended up failing.