I wouldn't even try to hit that button while on stage as a drummer. Here are three options;
1. Use the Windows On-Screen Keyboard, make it wide and short, position it below MC on your Screen, so that all of MC is shown above and neither will be covered by the other, then when you want a track to start playing, hit the space bar on the screen. Actually, the Microsoft On-Screen Keyboard stays Always on Top, so it could probably cover some part of MC and not be an issue. $0. Not a perfect solution.
OR
Use the "Free Virtual Keyboard" from Comfort Software Group instead of the Microsoft version. Search for it in the Windows Store.
2. Find an on-screen virtual Remote Control buttons App, with perhaps just the Left, Right, Up, Down, and OK buttons. If possible, set it to be Always On Top and position it over the corner of MC somewhere, perhaps bottom right. Press OK when you want the next track to play. Cheap probably, but I couldn't find a good one quickly. A configurable virtual keyboard could probably do it.
OR
Use the "Hot Virtual Keyboard" from Comfort Software Group instead of the Microsoft version. This one is fully configurable by the look, and so you could build your own on-screen keyboard for use at gigs. Maybe the Spacebar, Arrow Keys, and some shortcut keys to other functions you may want to use in MC? Or just one big PLAY button. That one is here:
https://hot-virtual-keyboard.com/ Free trial. Cheap licence.
3. Get a Musicians foot switch. (Midi foot controller.) There are cheap programmable foot switches, sort of like this one:
https://www.ebay.com.au/itm/PC-USB-Foot-Switch-Keyboard-Pedal-L7W9-/113040544669?_trksid=p2349526.m4383.l4275.c1#viTabs_0Program it to press enter or spacebar. Click it with your foot when you want the next track to play. A musician friend of mine uses a bunch of these sorts of switches with Apply devices and sophisticated software to select background beats, reverb, and so on while on stage. Your application is much simpler. Most are connected via USB, so you would need to have one available on your touchscreen device. Still a cheap solution.
Okay, there is a fourth option;
4. Learn how to edit MC skins, and with your new knowledge, increase the size of the controls you highlighted. That may have undesirable consequences for other parts of the interface though.
But wait, there's more!
5. Get someone to write (or find) a small App that just has a big PLAY button and sends an MCWS Play command to MC on your PC.
Or even;
6. Find an Android/iOS App that can remote control MC and has a big PLAY button, or is configurable.
...
I'm still here!
7. How about a wireless simple remote control like those used to seniors? Big buttons, and not many of them. Arrows and Play often. Of course a wireless connection may be a bit risky in the environment you will be in.