It depends on the manufacturer. Do you know what brand of rigid vang your boat has?
Seldon is a popular one, but we would need to know for sure.
I got a used Seldon vang, and found that the gas spring inside was seized. I was able to disassemble the vang and replace the gas spring.
As far as the topping lift (line from end of boom to the top of the mast), if it is adjustable (most are), you can try to loosen it when sailing so the sail doesn’t snag on it.
Once the vang is fixed, you could really do away with the topping lift. On my boat, I use the halyard as a topping lift while in the marina just to take the weight off the vang. But when sailing, I don’t have a topping lift.
Greg