I work at the same company as you and I use WebStorm for 99% of my tasks. I also have RubyMine installed and use that when I have to tweak some backend code. I tried using RubyMine for JavaScript but was unhappy with how it felt and I believe that WebStorm is faster because it has less plugins and language extensions running. Summary: Buy and use WebStorm for primary development and keep VS Code around for when you have to touch Ruby.