Duplicate Photos .JPG & HEIC

Hello,

I have held back from upgrading my Mac OS due to certain DJ software incompatibilities. Until yesterday, I was still using Sierra.

I upgraded my iPhone about a year ago to the XR and was importing photos not realizing they were coming in as .jpg since my OS didn't know what anything else was. Most recently, an update to my iPhone was causing importing issues with Photos, so after a chat with Apple, I was told I had to upgrade my OS. After plugging in my iphone with Catalina, Photo's thinks there are 2000+ 'new' photos because they are in the HEIC format. I'm in the midst of doing the full import, because I would like to have the newest file format.

How can I go about an automated duplicate detection deletion of all the same files that are now in .JPG and HEIC?