Plantronics Bluetooth Struggle with iPhone 13 Upgrade

I've been using a Plantronics (PLT) wireless headset for a long time now. After I upgraded from an iPhone 8 to an iPhone 13, they seemed to stop showing up in my Bluetooth settings. I looked online and found a closed discussion here and one of the replies that were dubbed helpful was as follows:

I found a solution for this, by holding the voice command button and the call button at the same time for a few seconds it resets the headset and it is visible in Bluetooth settings now

I'm not a big tech person but... I'm struggling to find those buttons and test the theory out. Can anyone help guide me in that direction or give me other solutions that don't include iPhone reboots?