Struggling with 6-Month-Old Sleep.

My baby turns 6 months next week and we are stuck in a cycle of contact sleeping. Until 3 months, he slept independently in his cot. Now, he only sleeps while being held or hugged. ​If we transfer him to his bed, he wakes instantly or lasts 30–60 minutes max. If held, he naps for 2 hours. His max total sleep is 12–13 hours with the help of contact naps or sleeping and last week it hit 8–10 hours when we tried forcing the bed. He is a very light sleeper, and we are now unable to do anything else during the day or night. How can we transition him back to his own surface without him losing sleep? We are exhausted and need a sustainable plan. He didn't have any sleeping schedule currently. Till feb he had a schedule with 2-3 nights waking for feed but he used to get back to sleep. But now sometimes he gets up and stays awake for 2-3 hours.