mojave – The system memory continues to increase

I am using macOS Mojave 10.14.6 (Appendix 2).

I have not noticed any unusual system memory issues, as with some other posts on the site, that say the system memory is more than 150 GB. From time to time, however, I check the memory usage of my system and the number is constantly increasing. According to my memory, the memory usage was 30 gigabytes a month ago. Two days ago, the storage management stated 40 GB. Today, about 42.5 GB are occupied on the system memory. I do not understand what happens, and since I have a small SSD on my MacBook, this memory expansion effect is very annoying.

What should be the ideal use of the system memory under macOS Mojave? How can I fix this problem to recover my lost memory? Does upgrading to macOS Catalina increase the memory usage of the system?

I've installed DaisyDisk as recommended by similar questions, but I can not fix it from DaisyDisk. (I am in the trial version)

There is 4 GB of space in "other volumes," but I have not partitioned my SSD yet. Is this memory used by the operating system as a swap?

Here is a screenshot:

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Note: It would be great if solutions do not require the installation of third-party apps unless this is required. Thanks!