Clanger in some scenarios a scheduled task may not be the best option.
Example: You don't have many programs open and the task will still run and clean memory unnecessarily. Or you opened heavy websites in the browser (especially Firefox that doesn't have very good memory management) in a short time and the task takes a long time to execute.
A program that does this dynamically according to memory usage seems to make more sense, but it has the downside of having to run in the background. So it's up to you what you prefer, unfortunately in any scenario there will be some sh*t or negative point.
Cleaning on demand may be the best option if you have the patience for it
But honestly I don't see much advantage in cleaning the memory these days, except in the case of Firefox that I see as an exception or with some other program that is poorly optimized. For Firefox it's something more urgent because browser is something that people usually keep open almost all the time. But it would be necessary to do tests to see if it makes any difference in practice.
Clearing the "working set" seems to be the only interesting option, it can be useful in situations like Firefox from what I understand. It clears memory in use by programs.
I don't know the difference between "System cache" and "Standby list", for me the 2 were the same thing.
Clearing the cache in memory (I believe it is the Standby list) you will lose performance, Windows keeps data in memory that is not in use in case you run the same program or need the same data again they are already in memory, thus avoiding a new read on the disk. But this memory can be used anytime if needed, Windows will free this memory if needed. Clearing this cache will cause programs that you have already run or data that have already been copied to have to be read again from disk, that is, the second time a program is executed instead of starting faster it will take longer to open.