You get this message for 2 reasons
- You are running out of file system storage so macOS cannot create swapfiles.
- This is a possibility on your system because you do not have much free space on your file system.
- If you have an application (or several applications) which are requesting excessive virtual memory address space.
- A process that requests virtual memory address space requires the macOS kernel_task to create virtual memory page tables to keep track of what address space each process is using.
- If a process (or set of processes) requests too much virtual memory, the macOS kernel_task virtual memory page tables becomes so large that macOS would have to take all of RAM to manage the page tables and not have any left over for the applications. Then a threshold is reached, macOS issue the "Your System has run out of Applications Memory"
NOTE: It does not need to be the applications listed in the dialog box, as the guilty party could be a background launch agent, launch daemon, or other tasks running in the background.
I see from the EtreCheck you are running Avid, so I assume you are handling very large production files. Your problem could be either lack of file system storage, or using too much virtual memory.
I look at whether you are using multiple similar large data set apps concurrently each processing very large data sets. They could be combined asking for excessive virtual memory address space. EtreCheck says your RAM cannot be upgraded, so you have to live with what you have.
And also look at whether you can free up some storage on your boot drive, as it could also be you are just running out of storage for swapfiles.
Finally, see if you can reduce the number of current large memory consuming apps you are running at the same time.