> I no longer enjoy building REST/CRUD (or GraphQL etc etc) style web applications This might be a problem with Haskell, since the majority of Haskell jobs I've seen (and had) are backend engineering jobs in support of web application and somewhat complex backend services layer. YMMV.

I work with a couple people who have transitioned into Haskell, from other dev positions. The usual pattern is that they are in a BE role in a related technology (kotlin, scheme, scala, scala), and have made open source contributions. I would recommend reading through "Haskell From First Principles", and getting comfortable with everything in there.

For a Haskell Aggregator I use: https://haskell.pl-a.net/