Place cabbage and radish in a large colander. Sprinkle liberally with salt and mix to combine. Set aside for 1 hour. Add additional salt, mix, and set aside 1 hour more. Rinse cabbage and let drain.
Meanwhile, combine garlic, onion, ginger, and rice vinegar in a blender. Add water and blend aromatic mixture on high power.
Transfer drained cabbage to a large bowl and add aromatic mixture. Add persimmon, cucumber, green onions, and red pepper flakes and mix well.
Transfer kimchi to airtight containers and refrigerate for 3 days.
Mix thyme, dill, rosemary, and garlic powder together in a small bowl. Rub over both sides of each pork belly strip. Let stand at room temperature, about 15 minutes.
Heat a large skillet over medium-high heat. Cook pork belly strips until well browned, about 7 minutes per side. Transfer to a paper towel-lined plate, reserving some grease in the skillet. Cut strips into bite-sized pieces.
Saute kimchi, garlic cloves, and scallions in the reserved grease over medium-high heat until starting to brown, about 3 minutes. Drain on a paper towel-lined plate.
Mix doenjang, gochujang, sesame oil, minced garlic, sesame seeds, rice wine, and brown sugar in a bowl to make ssamjang sauce.
Serve pork belly strips with kimchi, garlic, scallions, and ssamjang sauce.