There are suggestions to use sugar tax revenue to subsidize Mounjaro, but shouldn't the usage be determined before collecting the tax?

The idea is to curb sugar consumption for public health by increasing taxes and then allocating that revenue to welfare and health-related budgets... but I feel like the intended use of the funds is quite vague and ambiguous. I even heard arguments suggesting that the tax collected should be used for Mounjaro subsidies or coverage. It makes me wonder if they are trying to collect the money before even deciding exactly where the budget will go, lol... Rather than introducing a sugar tax, seeing prices rise, and watching the working-class economy get further crushed, I'm just worried and unsure of what the right answer is...