Multiple sub fields

Yeah I was gonna point you to the map field as a custom option but otherwise this request just can't happen. Per the screenshot on the module page showing what the db storage looks like, we're limited to what gets stored in a single row. This is an area where I'd recommend using Paragraphs as a wrapper that composes the title and a multi-valued custom field for the variations you're speaking of. It at least eliminates the need for child paragraphs that way. I myself still use paragraphs in the mix for scenarios like this.