We have to track pages from different domains. Previously those pages were tracking by google tag manager or tealium tag manager. So we have datalayer or utags on different pages. Right now, we want to consolidate the data tracking with DTM. In the case, what will be the best way to handle the data difference from page to page.
Thankfully, DTM will work with any data layer you throw at it - even more than one! The best practice is probably to leverage the ContextHub Tool to hook into your JSON objects, then create Data Elements that align with each of the elements in your data layers. Here's the documentation on ContextHub, you'll want to leverage the Custom Data Layer feature:
Hope that helps!