You did not give EtreCheck "Full Disk Access" which limits the information in the report (I think it would answer your question about "Other" processes). It may also provide some useful information from the summaries of recent logs.
The write speed of your SSD is extremely slow. At worst the speed should be no slower than half the read speed. Seeing an SSD write speed of less than 1200MB/s when the read speed is 2400MB/s means something is wrong here. Hard to say if it is hardware or software.
You can try running Disk Utility First Aid on the hidden Container. Within Disk Utility you may need to click "View" and select "Show All Devices" so that the hidden Container appears on the left pane of Disk Utility. Even if First Aid says everything is "Ok" click "Show Details" and scroll back through the report to see if any unfixed errors are listed. If there are any unfixed errors, then you will need to run First Aid from Internet Recovery Mode, otherwise you will need to erase the whole physical SSD before restoring from a backup.
You may want to run DriveDx and posting the complete DriveDx text report here using the "Additional Text" icon which looks like a piece of paper. Unfortunately apps like this don't always properly interpret the health of SSDs so it is best to manually interpret the health report. Unfortunately Apple SSDs don't contain a lot of health information, but it never hurts to look especially when your SSD write speed is so slow. It is possible your software issue is affecting the SSD's write speed.
I did notice something from Symantec is installed (only one item). I'm not sure what app that is for, but I would uninstall that Symantec app by following the developer's instructions. You have a lot of third party apps installed with which I am not familiar, so hopefully another more knowledgeable contributor will chime in regarding the results of the EtreCheck report since I am not a macOS software expert.
You can also check the Battery System Preferences. Power Nap can keep a Mac awake. Does any of your software have any settings which would keep the laptop working to prevent sleep?
Your battery is way above the 1,000 Cycle Count which usually means the battery is probably due for replacement because the battery capacity is likely getting really low and won't run on the battery for very long. Of course you are using Coconut Battery so I'm sure you are aware of your battery's current capacity.
