1) First of all, next time you get the urge to repeat the Salat, remind yourself that Allah doesn’t want you to repeat your salat. When you want to repeat the salat, who are you doing it for? Aren’t you praying for Allah? If yes, then he Allah is telling you I don’t want you to repeat if. If you repeat it then you’re not worshiping me. Keep this mind as it’s quite helpful.
2) Secondly, since you didn’t deliberately break your oath (it got broken due to OCD which you couldn’t control) you don’t have to pay kaffara by feeding 10 people or fasting, so don’t worry about that