What software can I use to use android tablet as a second touchscreen monitor?

What software can I use to use android tablet as a second monitor?

Splashtop crashes on me and there isn’t any forum for free users

Google remote desktop does a terrible job of simulating touchscreen idk why they wouldn’t just have touching the tablet screen simulate clicking or at least simulate touching the computer screen on a touchscreen

If any software recommendations could be made with security assurances… that would be good.

p.s. If the software has the added function of mirroring just a portion of my screen (because my tablet is smaller) that would be nice.