Check out the docs for email confirmation here: https://ihp.digitallyinduced.com/Guide/authentication.html#e... You'll see that most parts of the confirmation workflow actually happen inside your application. Only the actual controller implementation is part of IHP pro, and it's just 20 lines of code. So you can easy implement this yourself.

Generally IHP uses a lot of standard libraries of the Haskell ecosystem. So you can always break out of IHP when things don't work. It's not much more lock in than other frameworks in the space :)

Some more background on the ideas behind the pricing can be found here btw: https://ihp.digitallyinduced.com/Guide/ihp-pro.html