Prismas query engine is a complex piece of code and receives very little outside contributions. Moreover, Prisma only has bindings for JS/TypeScript and Go at the moment, so there is no way to consume Prisma from Scala. As a result, very few Scala developers know about Prisma.
We enjoyed Scala as a language, and the massive JVM ecosystem is a huge benefit. That said, we were forced to rewrite the query engine in Rust as we had a need for a more modular architecture enabling us to embed parts in JS and Go libraries. We looked at the Scala Native and Graal projects (spent 6 months building a prototype), but neither delivered a sufficiently low memory footprint. The Prisma2 rewrite to rust is a much more stable product, and we love the Rust language.
All the best to both the Scala and Rust ecosystems. Hugs.