How can I create a dynamic trade-off slider?

Hi! I appreciate any help on this.
For a study I'm looking to create a slider that displays a trade-off between two options. Participants have to decide how much of a resource to spend towards Option A, which automatically affects how much of that resource is left to spend on Option B. For example, when participants choose to spend 60% of their resources on Option A, the slider should automatically show that 40% goes toward Option B.
I can achieve this to some extent with the 'Constant Sum' question type, but a) this is not a dynamic item and b) I would prefer to have my item as a single-item.
This is what it should ideally look like: