Many orders gradual import

Hi,
I see from the documentation that you recommend changing the paging if you have many orders. However we have over 100k orders and wondering if there a way for this to sync in the background as it might take days, it will be nice if it handles the error/resume and retries.
I fill like it I add do it and enable the check if the order exist already it will take reeeally long time.
Any ideas?
Thanks in advance
Renzo