Mac not downloading Ventura

I have a 2019 Retina 4k 21.5in Mac. I was having trouble with very sluggish operation so I backed up files to Time Machine on an external hard drive and reinstalled the OS. I am not sure what OS is was running, but when I started looking for help with the sluggish operation over a year ago I was at least running Big Sur 11.6.1. When I used CNTRL + r and rebooted my computer to reinstall the OS, the version it wants to install is Catalina so now I am running 10.15.7. When I search for updates, I get a Checking for Updates and a a spinning wheel. I have attempted to go to the App Store to upgrade to any system and it gets stuck on Finding Update.

I have ample storage available, well over 800GB.

What steps should I take to be able to download Ventura?