Take a raw photo rather than scan which gives the greatest flexibility in post and the best quality. What you do next depends on the camera used and your access to software. I use Lightroom Classic so I would process there and export as JPEG-XL in Rec2020 Color space. JPEG-XL files can be up to 12 bit. JPEG-XL is superior to TIFF and PNG for working with in FCP HDR projects as it has all the benefits of these formats with potentially far smaller file sizes. I definitely would not use standard JPEG as these are only 8 bit. Adobe Camera Raw can do the same job.
All that said, unless the photo is very good quality, you won’t get great quality out. That is a small picture so don’t expect too much. As far as slides or negs are concerned, I would copy using a camera and a setup suitable for copying slides. The same holds - shoot in raw, process the raw and create a JPEG-XL file for import into FCP. This of course assumes you have a camera.