Stop active process by new command

[Shadow-of-eagle]

Hello,
first of all, I'm not an expert, so there might be a general solution to this, that I just don't know.
I am using Ubuntu 24.04. I use the Fly-Pie extension to choose my keyboard light. I realised it with an option which just runs the needed command. If I choise a dynamic effect (Ambient in my case) the effect starts as it should but I do not see an easy way to stop the process because the command is not executed in a Terminal. Because of this I can not choose a different effect. It would be quite handy, if a new command would stop the running process to be able to start a new one.
I apologise for any language or spelling errors english is not my mother tongue.