I've been scanning hundreds of old pictures, even Daguerrotypes and tintypes from 19th century. The Photos app, included with a Mac, is about all I need.

This is a Daguerrotype from the 1850s. It was an
image on metal that was barely visible at all. The blue
and red colors could be seen if you held it just right
in the light. It was full of rust-like spots and seemed
pretty sad. Can you believe, taken 175 years ago!
I may have used GraphicConverter ($40) for some work before loading them into Photos-- especially for cropping and rotating from the scanning. But Photos has gotten more powerful since then.
Pictures like these


from 1900 and 1878 were quite a mess when I scanned them. One decision is when to stop -- they should continue to look old!
If you need masks to isolate the subject or sky, I've been trying out Photomator ($30/year or $80) with good success-- but I haven't really used it for old pictures.