But makes your life easier, especially when you’re a noob.
What you are saying is ‘Freemium’ software. Free software in our sense is free to do whatever we want, following its license, ‘Free as in Freedom.’
You can look at base16 project, they keep templates for many apps, and you can generate themes for any app you want. I used to use ‘flavours’ for theme management, but now I have settled with gruvbox-dark-hard
runit gang !