So the first point is obvious - baseline premiums go up every year usually. Depending on your family structure, that $200 increase might not even be all that much in terms of percentage.
On the 2nd possibility - since your premium tax credit is based on the 2nd-lowest cost silver plan, if that 2nd lowest cost silver plan goes down, your premium credit goes down dollar for dollar at the same income level, so the net price goes up dollar for dollar.
Is there new competition in your area? That's what happened with us - until 2021 there were only 2 silver plans available, so PTC was high for everyone in our county based on a high-end silver plan. Enter 3 or 4 new insurance companies, and suddenly there's competition at every price level, and PTC is substantially lower for everyone.