I wanted to let all of you know how it went with the installation of physical buttons that I have bought recently:
https://www.reddit.com/r/Leapmotor/s/vAIGwZknt2
According to the video instructions, there are 2 ways to install them. I chose the option no. 1, which was quite labor intensive. If you are not very experienced with fiddling with the interior parts, I would recommend the option no. 2.
After the difficult installation I was quite disappointed as it didn't work. I have contacted the COSYEV team, they were very helpful and quickly determined, that the wiring of EU version is different than Chinese. They sent me the manual on how to change the connection of two wires and it started to work! I am very satisfied with the overall effect and the usability. Hopefully they will start to offer the buttons ready for the EU market so that more people could make use of them.