Difference between the imac destop and imac desktop pro

Basically an iMac Pro is Pro iMac for working professional creatives.

The standard iMac line is the iMac for consumers/prosumers that have less demanding computing and creative needs.

So, you seem to be just fine with looking at the standard, consumer level iMac and NOT the iMac Pro.

Also, you must be behind the times and have not kept up on where technology has been going.

There hasn't been an optical drive in any Mac in the last 7 years.

There are NO optical CD/DVD/Blu-ray drives in any Mac.

The following may help:

iMac - Technical Specifications - Apple

iMac Pro - Technical Specifications - Apple

The fact that you have held onto your old iMac as long as you have pretty much indicates a standard iMac would be ideal for you. It’s always comes down to what do you use the computer for. If you were a professional graphic artist, someone that does 3D graphics or music production or even movies then an iMac Pro may be of interest.

my guess is you likely don’t fit any of those profiles.

You won't find anything in the tech specs about a dvd or disk player because they are not built into the machines. You can get an external USB dvd burner drive to add that capability though. Check out the on-line store at OWC they also offer BluRay options.

Another option for overcoming the lack of a built-in CD/DVD drive is Apple's Remote Drive:

Use the CD or DVD drive from another computer with your Mac - Apple Support

I use the optical drive in my 2012 MacBook Pro when I need to read CD files on my 2017 iMac. We also have an older iMac of the workstation that has an optical drive.

This even works with the drives in most Windows computers.