SD card formatted as internal storage Recovery Data
This question appears to be a  duplicate of How to decrypt Adopted Storage?
in many regards, but if I understand it correctly, the following things happened and one step makes it unique:


You adopted the microSD card as internal storage
You removed it from the device (reason isn't relevant)
While the microSD card was removed, you factory reset (formatted) the
phone
You re-inserted the microSD card after the reset was complete, and
the data is unreadable


If this is the correct summation of your situation, then I am sorry, but your data on the microSD card is lost permanently, and cannot be recovered.

When an SD card is "adopted" as internal storage, it is encrypted with a random encryption token (a digital "key" so to speak) so that data can only be read or written to by that device for security and privacy. Any data recovery attempt of the information on the card requires the encryption token from the device, which is generated randomly when the storage card is adopted, if you formatted the device the token was permanently erased like all other transient device data, and the storage cannot be decrypted or recovered by any known means.

Your only real option now is to reformat the card and start clean, and unless you really need the space as internal, use the card as external (portable) storage.

For more clarity in to why this is impossible, and what is necessary for the data to be recovered, you can reference this question.