Yes, that is true and well known but it does NOT explain this problem. It is also true that both MS and Apple do write (or contract) some "universal" drivers to support legacy printers that are no longer supported or updated for new Windows or Mac OS by the original printer manufacturers.
I am a retired IT pro who managed the printer lab for a very large company and set worldwide standards for all their printers. I have 40+ years of professional experience with printers. I have written printer drivers, myself.
If there were a problem with the printer drivers, the problem would occur on many different applications but NOT with drivers supplied by other manufacturers.
This problem ONLY occurs when printing Mac Excel workbooks. And the problem exists if you print the Excel workbook on a brand new Mac Studio or a 12 year-old-MacBook. I have many printers from different suppliers and more than a dozen drivers installed on each of my Macs. They ALL have the same problem when printing Excel files.
Some of my workbooks are stuck with printing 12 copies, others default to 1, 2, or 3.
For "fun" I created some new spreadsheets yesterday and printed them for the first time using different numbers of copies and it replicated my earlier results.