Pat the chicken dry and season lightly with salt. Heat the avocado oil in a wide, heavy pot over medium-high heat. Brown the thighs skin side down 6 to 7 minutes until deep gold, then flip for 2 minutes. Work in two batches if needed.
Pour off all but 1 tablespoon of fat. Add the smashed garlic and cook 1 minute until fragrant.
Add the vinegar, coconut aminos, water, bay leaves and cracked peppercorns. Bring to a simmer without stirring, then cover, reduce the heat to low and cook 30 minutes, turning the chicken once.
Uncover and raise the heat to medium. Simmer 10 to 15 minutes, spooning the sauce over the chicken, until it reduces to a glossy glaze. Taste, and add the maple syrup if it tastes too sharp.
Heat the broiler. Move the chicken skin side up to a sheet pan and broil 3 to 4 minutes until the skin crackles and darkens at the edges.
Serve the chicken over the brown rice with the sauce and softened garlic spooned on top, the sauteed bok choy alongside and scallions over everything.