I am facing one issue one data entity which is taking long time to import record 30 minutes for 1 record in UAT this is purely standard entity and we have not done any customization on top of it. I have restored the database from UAT to my local dev environment and found same issue in my local dev env
So I have debugged the DMF importing in local dev and found one issue which is Table -> EntAssetJobtypeDefault -> insert -> super() it is standard method and in this when it goes to super it gets hanged.
I face similar issue long back (couple of years) in AX 2012 , but not sure how to resolve it UAT and in my local dev environment, kindly provide your input.