New iMac says it's 2017

That is the very entry-level "Edu-iMac" and has not been updated since 2017. The date is not the year of production but the year introduced. This from the MacTracker database:

That means it is still in production.

Apple continuously manufactured 2012 MacBook Pros from June 2012 through October 2016 and the model designation never changed.

The free utility Coconut Battery (https://www.coconut-flavour.com/coconutbattery/) will show the date your computer was built.

As an aside, I am not surprised by the report of slow." It has a dual core processor instead of the much more capable quad-core processors used in the next model up ( (US$200 more). These are bench marks for yours and the next model up:

[from the MacTracker database]

That is a 61 percent increase in performance increase for an 18 percent increase in cost.

Download and run Etrecheck. Etrecheck is a diagnostic tool that was developed by one of the most respected users here in the ASC and recommended by Apple Support  to provide a snapshot of the system and help identify the more obvious culprits that can adversely affect a Mac's performance.

Copy the report

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

IMPORTANT:

Before running Etrecheck assign Full Disk Access to Etrecheck in the Etrecheck's Privacy preference pane so that it can get additional information from the Console and log files for the report:

Also click and read the About info to further permit full disk access.

Then we can examine the report and see if we can determine what might be causing the problem.

If it is the "iMac Pro" the most current release of that model was December 2017. It may have been manufactured last week or month but it hasn't been redesigned or had a hardware update since 2017.

However, you shouldn't be seeing that kind of performance. I can't help with that but if someone else here doesn't help soon, you may want to make a new post with the performance issues in the title,