Glad I could help out! Also, no need for a separate thread, I feel like it’s still pretty relevant to your initial question and I’m happy to give my two cents.
Think of both types of columns as being suited for different uses, so unless you feel like manually splitting the copy (which isn’t ideal for dynamic CMS data, for example) I’d recommend using the text columns for any typesetting. Splitting up other types of content (like text next to an image) is best suited for flexbox/grid, but you can always use the two together to create more interesting layout options.