I don't know any way of increase the size of just the operating buttons on EW. About the only thing I can think of to try is to increase the scale of the display on the control screen in Display Settings. Unfortunately it would increase the size of everything on the screen so it would have some drawbacks.
Maybe one of the EW Support Team has some other idea(s).
That's what I would also suggest Don.
The other option is to get a Stream Deck and use that for controlling EW live. It won't help when creating schedules and editing/adding songs and presentations, but it would help with running the service live. The buttons are large and easy to press. You can actually use the Stream Deck plugin with the Stream Deck app on a phone or tablet, but there is a subscription for that. $2.99/m or $24.99/y.
Here's a video we did on Stream Deck to give you an idea of what it is and does in case you don't know.
I would love to setup a Stream Deck Mini on our podium with only two buttons loaded with just advance slide and back. Our Pastor is over 6 ft 4, weighs almost 400 lbs, and has fingers that are like Polish Sausages and constantly presses the wrong button on his presenter remote during a sermon. Working the EW Remote app on a phone/tablet isn't a viable option either.
Is there an easy way to increase the size of the operating buttons and other operating text on EW 7.3? I am 77 with slightly shaky hands and diminished visual acuity. Trying to click the operators can be challenging and embarrassing when I land on the wrong spot. If they could be made slightly larger it was be a great blessing.