A couple of my heuristics
1. Running a smaller business takes the same amount of work as running a bigger one.
2. A running a failing business takes more of the owner’s energy than running a successful one.
This thread exemplifies at least one of them because if the plan was a bigger business, you would not be spending time on alternatives to Stripe.
Business ideas can be feasible but not viable. If it does not pencil out, it doe not pencil out.