Cartridges for Switch don’t hold save files.
I don’t know what caused the split (assumingly your OFW and CFW both have the same profiles, but they’re treated as separated on the sysMMC and emuMMC now) and I doubt I know how to merge them back into one, aside from only using CFW and bringing CFW online.
(could be related to updating game or firmware of CFW, and leave OFW unupdated)
[I don’t use emuMMC, so my CFW is on sysMMC and I bring CFW online. Don’t use injections on my save tho]
basically, you want to use your hacked save on OFW, I understand that much. However given your profiles are separate now, as I’ve said, no clue how to remerge them. Maybe someone with more experience with this would come along. In any case, this isn’t a PKHeX issue.