Balatro wasn't made in a month! It took 2.5 years in fact.
Given how polished your game is already, I'd say you'd come close with a roadmap and a few months. Maybe a Kickstarter further down the road? I think it's all worth looking into!
As for how much further it can go, there are plenty of areas to innovate IMO. Maybe you have to fill up your "cart" with products using the same grid logic before using coupons, giving you control over what types of stuff you take. Maybe the store adapts to your meat coupon strat by removing meat (something like the boss effects from balatro that disable suits). Maybe the win condition involves taking X value of products each round to make a larger dent in the company's profit margin (requires putting more stuff in your cart, which risks you not being able to afford it).