Shopify Checkout Blocks

Its a good start, but I'm hoping it expands and becomes better with more features. I currently have a date picker that I can't exclude disabled days as lead days, so as soon as it gets to Thursday customers are able to selected Monday when it should be Tuesday or later as I have excluded weekends as delivery days but no way to exclude as a lead day. I assume this will also not work for blackout days. I would of talked directly to the app developers but there is no dedicated contact service for the app but the generic shopify help, who, when I explained I wanted to add function to a checkout block dynamic content block, wrote a reply ignoring the app and included liquid code which I have no way of deploying as I have no access to the checkout code.

Nice, but why should I pay 200$ when there are similar apps for 5$/month?