Imac 27 Retina A1419 - kernel panic

First, there is no reason to ever install or run any 3rd party "cleaning", "optimizing", "speed-up", anti-virus, VPN or security apps on your Mac.  This user tip describes what you need to know and do in order to protect your Mac: Effective defenses against malware and other threats - Apple Community.  

There are no known viruses, i.e. self propagating, for Macs.  There are, however, adware and malware which require the user to install although unwittingly most of the time thru sneaky links, etc.   

Anti Virus developers try to group all types as viruses into their ad campaigns of fear.  They do a poor job of the detecting and isolating the adware and malware.  Since there are no viruses these apps use up a lot of system resources searching for what is non-existent and adversely affect system and app performance.

There is one app, Malwarebytes, which was developed by a long time contributor to these forums and a highly respected member of the computer security community, that is desshoigned solely to seek out adware and known malware and remove it.  The free version is more than adequate for most users.  

Also, unless you're using a true VPN tunnel, such as between you and your employer's or bank's servers, they are useless from a privacy standpoint: Public VPN's are anything but private.  

As you've already been warned CleanMyMac is considered akin to malware by most of the experienced users in these forums. Uninstall according to the developer's instructions as HWTech suggested.

Also uninstall Tunnelblick. If you're using it for privacy there's no assurance you have it.

Also where did you get the additional RAM? Apple or a 3rd party vendor? If 3rd party who? Macs are very sensitive to RAM quality and with the newer systems they are even more picky. Even if a module meets the specs doesn't mean it'll work indefinitely in a Mac. If it's Apple, Crucial.com or OWC (MacSales.com) we can rule out RAM issues.

Uninstall CleanMyMac by following the developer's instructions. Anti-virus apps, cleaning apps, and third party security software is not needed on a Mac and usually causes more problems than they solve plus they impact system performance. These forums are full of posts with people having these issues with CMM.

If you still have issues, then disconnect all external devices from the iMac (except for you keyboard & mouse) in case one of them is causing a problem. The one kernel panic may be related to a USB drive. Run EtreCheck again and post the new report.

You can also try running the Apple Diagnostics.

I don't see any of the usual suspects but do see a couple of apps that might be of concern:

1 - Google Chrome - is a know resource hog and data miner and is doing that on your iMac. It's not as secure as Safari or Firefox so if you don't absolutely need it uninstall according to the developer's instructions.

2 - Tunnelblick - be aware that unless you're using a true VPN tunnel, such as between you and your employer's, school's or bank's servers, they are useless from a privacy standpoint: Public VPN's are anything but private.  Again, if unneeded uninstall according to the developer's instructions.

You can check to see if you've removed all of the supporting files by downloading and running the shareware app Find Any File to search for any files with the application's or the developer's name in the file name.  For the software mentioned you'd do the following search(es): 

1 - Name contains tunnelblick

2 - Names contains chrome

Any files that are found can be dragged from the search results window to the Desktop or Trash bin in the Dock for deletion.

FAF can search areas that Spotlight can't like invisible folders, system folders and packages.  

looks like you have endpoint and possibly another security program. if you run multiple malware apps it can cause a nightmare, or none at all; it's finicky.

Etrecheck is a utility to identify whats installed on your Mac, it won't provide any private information

https://etrecheck.com

it was developed by a contributor to this forum. if you feel inclined to seek a more opinions about it's legitimacy, I always suggest you go with that instinct.

[edit]

it should be free or at least the parts you need from it to run a report. I don't get a commission for you using or deciding to buy it.