My brother had two of these broken in the exact same way when he bought his Protege.
I came to the same conclusion after I took the old ones apart to see how they broke and wondered if I could just buy replacement gears or epoxy them, but couldn't find any options online and I don't know how well Epoxy would hold up. I did think about 3D printing replacements, but I doubt they'd hold up either.
I ended up going to the junkyard and getting two replacement actuators for like $20 total or something like that (didn't cost enough for me to remember exactly how much). $40 a piece is kind of stupid for what they actually are, but compared to prices for other cars, it's not too bad even if you just buy the whole assembly new.
Try car-part.com if you want to be double sure that your local yard has a Protege, or just walk in and ask. Sedan and Wagon actuators are the same, but keep in mind that there are two different actuator models used in the doors (I think it's A & B and they are just reversed symmetrically), so if you get the whole assembly, make sure to get the right ones unless you plan to just swap the gear only.