I feel like I knew what this thing was right up until I had one. Two tool id site had no idea, and one said it’s a ball joint separator, but I can’t find any that look like this, and I swear I’ve seen them in stores, but can’t remember where.
Maybe a type of bearing press?
I got really good with one because when I was young I’d always forget to put the flare nut on first lol. End up doing it twice every time. My uncle used to get pissed.