Mac is too slow = Ventura

Can you provide me with instructions as to how to clone my hard drive to an external SSD?

The reason your iMac is slow is due to the 5400-rpm hard drive. While this hard drive found in your Mac is perfectly suited to light tasks, such as email, web browsing, etc., for more advanced tasks, and for users who want the maximum performance from their Mac, this hard drive does have its limitations. Luckily, you can use an external SSD as your startup disk to run macOS and all your data from that. It will make your Mac 10 to 40 times faster for storage, and in turn, make your entire Mac system much faster. For more info, instructions, and what external SSD to buy, please see: How to Setup and Use an External SSD as your Startup Disk on a Desktop Mac - Apple Community.

Jack

Rerun Etrecheck and copy and paste the results into your reply as follows:

Copy the report (important to do it this way)

and use the Additional Text button to paste the report in your reply.

Then we can evaluate the report to see if we can determine the cause of the problem.

I don't see any of the usual suspects in the report. However, unless you're using a true VPN tunnel, such as between you and your employer, school or bank's servers, they are useless from a privacy standpoint.  Read these two articles: Public VPN's are anything but private and Former Malware Distributor Kape Technologies Now Owns ExpressVPN, CyberGhost, Private Internet Access, Zenmate, and a Collection of VPN “Review” Websites. 

You have the slowest HDD available in your iMac, a 5400 rpm drive. You can improve the speed of the Mac as far a boot time, application and file launch times are concerned with an eternal SSD that you've cloned your internal drive to and are booting and running from it. I recommend drives from OWC (MacSales.com) as they have proven reliability, excellent customer support and warranties.  Consider one of these depending on your budget and needs: 

1.0TB OWC Envoy Pro FX Thunderbolt 3 + USB-C Portable NVMe SSD

1.0TB OWC Envoy Pro SX Rugged Portable NVMe SSD with Thunderbolt/USB4

1.0TB OWC Envoy Pro Elektron USB-C portable NVMe SSD

Envoy Pro EX with USB-C or USB 3

OWC Envoy Pro SX - up to 2847 MB/s 

For your model contact OWC's customer support and get their recommendation for the SSD model that would best suited to your iMac model, work requirements and budget.  They may have additional models other than those I've shown above.

First erase the external SSD and format it to APFS. Then use Carbon Copy Cloner. In its window put the destination (external SSD) in the middle box, Control (right) - click on it and select "Legacy Bottle Backup Assistant…" from the contextual menu.

Then CCC will finish the job.

Please post you EtreCheck Pro report,

as per > How to use the Add Text Feature When Post… - Apple Community