Hello again!
tl;dr: new: number entities, recommended config here.
Inspired by the project actually being used I spent some time on it this weekend 
Thanks to the information collected by Mahko_Mahko I was able to add two essential commands to my project.
Stop command
It is now possible to add a stop button and/or use the stop() command in lambdas. In my case the desk stops immediately, so no soft stop unfortunately. (I guess it’s like an emergency break so it’s for security reasons?)
Go to specified height
There now is a method goto_height(float height) to specify a height in centimeters that the desk will then move to. This enabled the next new feature.
Number entities
Starting with the current height of the desk I added number entities which allow to show and control a numeric value.
In other words you can now use a numeric input to control the height of the desk!
I plan to implement this for other values too like the height in percent or the stored positions.
Everything is still optional and all previous features are still available. So you can choose to use numbers, sensors, buttons and/or lambdas in any combination. 
You can find a full blown example config here.
A recommended config is also available.
Let me know what you think! Here or via GitHub Issues!