If you have an application running, you can right click on the item in the unity starter, select "Lock to Launcher", and the program will stay there even if it is closed.
The problem is that the new launcher now has the title the window had when it was locked. This is often not only the name of the program, but also includes additional information, like
app.js - My Project - Visual Studio Code. It will stay even after unlocking the app.
Is it possible to rename the launcher without taking the hassle of creating a
.desktop file? Where does unity saves the information of locked launchers?