How to Add a Second Monitor to Dell Tower Plus

I just rec'd my new Dell Tower Plus and I need to add a second monitor. I already have a cord that goes from the monitor (with a DVI output) that has an HDMI output, but this desktop only has one HDMI input which is already in use.

I have an HDMI to a USB-C adapter and I've plugged this adapter (using one of those tiny USB to USB-C adapters) into all of the USB inputs on the back without luck. (This adapter didn't work on my existing HP desktop either.)

I'm wondering if this adapter is bad or there's a setting that I have to use?

If I have to buy another cord, should I purchase a DVI to USB cord or a DVI to a Thunderbolt 4?

Safe to say the tiny USB to USB-C adapter isn't the issue? Since the DVI to HDMI cord worked on my old HP, but putting the HDMI to USB adapter on and plugging it into the USB input didn't work on the HP either. (I'm guessing either I'm missing a setting on both computers or the HMDI to USB adapter is bad!)

THANKS