2019 iMac not connecting to external HP27h monitor

I just purchased a new HP 27h monitor to use as an external monitor next to my iMac. No connection issues with my other Mac devices (2018 MacBook Pro laptop/Monterey 12.6.5 & 2021 iMac/Monterey 12.5.1).

It will not connect to my 2019 iMac running on Ventura 13.4.

I suspect that my 4-year-old iMac running the latest operating system may be the issue. Can anyone confirm this?

I have always used a second monitor for my workspace set-up, and I am feeling very claustrophobic being limited to just one monitor now. Is the solution to downgrade the operating system to Monterey 12.6?

Do Thunderbolt ports (USB-3) go bad? Because it seems that one of my ports is not connecting properly. But I have a working one, as my phone is getting a charging signal. I am ensuring the monitor is connected to that one, and still, no input signal is being found.