how was the card initially formatted? as internal or as portable storage?

 

Suggest you try connecting the SD-card to a computer. Mac or PC, and see that can mount and read it.

 

You have to watch how android names its storages, SD card is usually the internal, phone storage, and external or removable storage will be your removable SD card.
You may have lost them all

 

If your card was formatted as Internal, any data on that card is now lost. It's no longer accessible because when a microSD card is formatted as internal, its file system is altered (to be identical with your phone's internal storage) and its encrypted (also so match up with your phone's internal storage).

When you did that Factory Reset that also wiped the encryption key. That now missing encryption key was what linked your phone's internal storage to the 'Internal' microSD card so at this point any data on that card is no longer accessible. Reformat the card to reuse it again -- the data is essentially lost but you can still keep using the card again once it's been reformatted.
But you really should try to mount the card in a computer first to check it. If it was formatted as Portable instead your data might still be there or at least recoverable.