Thanks Barney. Can you explain more or link to an article that goes into this more deeply?
There isn't anyone who knows macOS better than Apple, so expecting any tools to improve things is unrealistic.
macOS has always taken care of itself. There isn't anything to "maintain."
The system is mounted read-only from a sealed snapshot of the System volume. There isn't any way it gets altered or corrupted. There is nothing in the OS to maintain.
Some of those tools mentioned by AlWeir have useful one-off functions for enabling hidden features or maybe clearing a cache that is actually corrupted (rarely happens).
Unfortunately, they also come with automated suites of "maintenance" tools that are completely unnecessary and can cause problems. None of them are going to improve performance or prevent some malfunction.
If you want a computer you have to piddle with, use Linux.