I have a couple old pocket knives that belonged to my grandfather. I've looked at a lot of information about removing rust, polishing, etc. I used a gun cleaning solvent with wet/dry sandpaper to take off the heavy rust and brass wire brushes. I have polishing cloths and metal polish. I got them looking a lot better, but there is some damage to the metal itself on the oldest knife. It looks dimpled. Is there anything that can be done to help with the damage short of machinery to refinish the blade or something? I'm pretty new/inexperienced so I'm open to suggestions as long as it doesn't require buying expensive tools. The knife that is the worst was from my grandfather's tackle box so it was used hard.
Since you already "ruined" the patina... Leave them alone. Full restoration only erases the wear that is their story.
Those rust pock marks can only be addressed by adding metal via welding with a suitable filler and then finishing to even the surface. That would require full disassembly, which likely means replacing pins/rivets.
You could do a sort of kintsugi with a compatible material, but how that turns out depends entirely on the material and process.