2019 27in 5K iMac running slowly

There are a lot of problems with your 2019 27" iMac.

I see some issues in your report. First is you have Nord VPN installed which is considered malware by most experienced users on these forums. Mac OS is catlike in that it cleans itself, Mac OS does not benefit from nor does it require any of the following types of third party apps:

·      Antivirus Apps

·      Cleaning Apps

·      Security Apps

·      VPN Apps

·      Maintenance Apps

What these types of apps do is the exact opposite of what users want. They make Mac OS slow, appear buggy, can damage Mac OS and sometimes create unwanted behaviors. In short, they are really bad news!

So the first order of business for your computer is that you need to locate the developers. uninstall instructions for Nord VPN and please uninstall Nord VPN. Because Nord VPN is pretty nasty stuff it tends to leave parts behind after being uninstalled, a testimony to how poorly written the app is! To fully ensure you have uninstalled it please download the free version of FindAnyFile directly from the developer. Then have it search your system for the following:

·      Nord VPN

Have it Trash any files with those names in them and then ensure the Trash is empty. 

Your 2019 iMac also has a Fusion Drive which is small SSD fused with software to a spinning Hard Drive. The HD portion of the Fusion Drive may either be failing or it may have become unfused. If it has only become unfused then it can be re-fused. Apple explains how to do this in How to fix a split Fusion Drive - Apple Support.

If the HD is failing then I'd recommend simply replacing the Fusion Drive with an external SSD. You can check to see if the HD is failing by downloading the free version of DriveDX and test the hard drive, not the Fusion Drive just the hard disk!! If ANY errors appear that means the HD is failing.

Next, there is ZERO evidence that indicates you back up the computer. This is a MAJOR issue and it means your data is at risk. You have been EXTREMELY lucky that you have not already lost data, so this issue needs to be addressed ASAP!!! We recommend using Time Machine which is pre-installed on the computer and only requires and External Hard Disk to backup to, many experienced users recommend the OWC Mercury Elite Pro as their backup drive. Why this drive rather than a Walmart or similar drive.... reasonable cost, high reliability, ease of use, great support from the vendor.

Also, you have Citrix installed on the computer. So it appears you use the computer for work which is fine. If this is still the case ensure your version of Citrix is up-to-date. Finally if I am correct about you using the computer for work, if your employer demands that you use a VPN to access their systems, then THEY should supply a professional VPN app!! Using freebee VPNs like NORD is dangerous and highly not recommended unless you are okay with living with an unstable system.

Download and run the free version of EtreCheckPro, from > https://etrecheck.com/en/index.html

Then post back here with the Report, as per > How to use the Add Text Feature When Post… - Apple Community

I would not try to change internal drive to an SSD. Use an external TB drive which will be faster than your internal which is what I did. This is assuming you have resolved any issues with your system.

+1

Instead of risking internal damage, startup and run from an external SSD.

see > Use an external SSD as your startup disk … - Apple Community

Completely uninstall Nord VPN, it is not needed to protect your iMac.

+1, please post the requested EtreCheck report of the computer.

Run a new EtreCheck report and analyze it to see if there is ANY evidence (meaning anything that shows Nord VPN) in, take your time and read it carefully.

As for the external DVD you can do that if you want, the drive I recommend is the https://eshop.macsales.com/item/OWC/TB3ENVPFX02/ and instructions for making an external SSD as your boot drive are in How to setup an external SSD as your startup disk