Controlling Android phone with Sevensquare under Ubuntu 18.10 does not work

I would like to remotely control my Android device (a Motorola Moto G5 running LineageOS 15.1) with my Ubuntu 18.10 laptop. So, I watched this tutorial and got this result instead of this.

Not only is the picture heavily distorted. I am also not able to control my device properly. Sevensquare barely reacts to my commands – and if it does, it lags behind and fails miserably.

Is there a way to fix this or are there good (and working) alternatives for Ubuntu?