Recover accidentally to APFS formatted HDD

I was in the process of upgrading my moms late 2014 mac mini running high Sierra with a SSD and clone the original 500GB HDD to the newly added SSD. While trying to format the new SSD to a bootable format, I accidentally chose the original HDD to format as GUID / APFS instead of the new SSD 😟. I used the preset fast method in disk utility when formatting. Unfortunately there is no Backup of the original HDD.

Can anyone give me advice on how to try to recover as much as data as possible or even put the HDD back in its previous state? Do I need to format the old drive back to HFS? Will the First Aid in disk utility be any help or will it do even more damage to the lost files?

I am currently doing a clean install of high sierra on the new SSD and will see if the test version of Data Rescue 4 is any help.