I think they need their own time. Like even for human, we need some time apart after fight. Try to separate their routine as much as you can; dog-walking time, bath time, eating time(make sure they eat in separate places) and even when sleeping (make sure they don’t sleep together. Put them in separate rooms). If all of the stages does not work, two or three weeks of separation will be the healthiest way. My dogs used to fight like crazy, so I made my sister to take one for a month. And after a month, the two were much better. Do not think this of getting rid of your dog, it is rather a dog vacation!