In fact, you've already used CodeMirror yourself if you've ever edited your theme on Shopify. Shopify's official theme editor is CodeMirror with custom Liquid syntax highlighting and Multiplexing. Doing a quick Google search, it looks like many people have created some 3rd party libraries to attempt to mimic the Shopify experience for your own website, such as https://www.npmjs.com/package/codemirror-liquid-multiplex.
If your company uses CodeMirror with Liquid and you're looking for an even better Liquid-editing experience, then it's your lucky day! You can now take advantage of Dropkiq's Liquid autocompletion with CodeMirror with no extra work. You simply use DropkiqUI the same way as with any other input type. Things just work like magic! Take a look at the demo to see everything in action, or you can look at the documentation to see how to set this up for yourself.
As always, please reach out to me anytime at firstname.lastname@example.org if you're interested in using Dropkiq at your company and you use a WYSIWYG editor that is not listed.