I need to upgrade my iMac from Ventura in order to run software I need

Your iMac needs to have a hardware model year of 2019 or better to upgrade past Ventura.

macOS Sonoma is compatible with these computers - Apple Support

macOS Sequoia is compatible with these computers - Apple Support

RedWolf wrote:

I can't upgrade beyond Ventura because I have a 2017 27" iMac. I would have a new one if only Apple brought back the 27" iMac.

To be constructive

Purchase the newer M4 Mac Mini with a base of 16 GM Unified RAM and a 27 " or larger Display

This display also has the ability to Rotate 90 degrees

Exactly what mode iMac do you have? That will determine what version of macOS it is capable of running.

you can suggest they do by using their feedback channels

Product Feedback - Apple

You can do better than a 27" iMac this way: a 10 Core Mac Mini M4 with 16 GB RAM and 1 TB SSD with a 32" LG 4k monitor w/speakers is $1418 w/tax which is $650 less than a similarly configured new 24" iMac.

You can save even more if you drop down to a 27" monitor w or w/o speakers. I opted for more screen real estate. It is screamingly fast.

I can't upgrade beyond Ventura because I have a 2017 27" iMac. I would have a new one if only Apple brought back the 27" iMac.