At some point in early 2022, my predecessor, for whatever reason, decided to create a new company file on QBO. It is now my task to combine the companies into 1 file so that we have all the current and historical data in one company instead of 2022 in one and anything prior in another. 

When I contacted QB help I was given the option to export and import each account separately. I am worried about 1) the loss of details between the companies, as in, who entered the transaction, or attached files to various JEs; 2) imports seem to have a cap at 1000 lines, just the journal export for the month of November was nearly 1300 lines. 

I was thinking about possibly exporting the historical company into QB Desktop then creating a backup of that file and then uploading that backup into the current company inside QBO. Has anyone done anything like this and if so how did it work? Or do you have any suggestions on any other way to combine the companies without spending a week to a month of solid export/manipulate/import?