iMac running very slow

Hello,

The reason your iMac may feel slow is due to the 5400-rpm hard disk. While this hard disk found in your Mac is perfectly suited to light tasks, such as email and web browsing, but for more advanced tasks, and for users who want the maximum performance from their Mac, this hard drive does have its limitations. However, you can use an external SSD as your startup disk to run macOS and access your data. It will make your Mac 10 to 40 times faster for storage, and in turn, make your entire Mac much faster and even better.

To learn more, see: Use an external SSD as your startup disk … - Apple Community.

Jack

In addition to Jack-19's excellent comments, your Mac does not have enough RAM to run multiple apps simultaneously ... at least, not at the time you created this report.

How do I know? By this section in the report:

Virtual Memory Information:

Physical RAM: 8 GB

Free RAM: 28 MB

Used RAM: 5.23 GB

Cached files: 2.74 GB

Available RAM: 2.77 GB

Swap Used: 768 KB

This value should be zero. What is happening, is that macOS is temporarily moving one or more apps from RAM into your Mac's hard drive ... which is much slower. This is one of the reasons that your Mac is running very slowly.

Uninstall Clario, antivirus apps are not required and slow things down as well as messing with the OS.

Don’t have Malwarebytes running in the background, just run a scan as needed and shut down afterwards.