Cook chopped bacon over medium-high heat in a Dutch oven until nearly crisp.
Add diced onions to the bacon and drippings, cooking until softened and lightly browned, about 6–8 minutes.
Stir in minced garlic, seasoned salt, black pepper, and crushed red pepper flakes, cooking until garlic is fragrant, about 1 minute.
Add collard greens and sugar, stirring to coat evenly.
Pour in vegetable stock, place ham hocks and bay leaf in the pot, and bring to a simmer over medium-high heat.
Reduce heat to low, cover, and simmer undisturbed for 1 1/2 to 2 hours until greens are tender and ham hocks are fork-tender.
Remove from heat, discard bay leaf, and transfer ham hocks to a cutting board to cool slightly.
Remove and discard skin from ham hocks; shred meat with a fork and return shredded meat to the pot.
Stir in apple cider vinegar and adjust seasoning with additional salt as desired.
Serve immediately.