A move from SPA means business logic moves to the backend and becomes hypermedia-driven, so the correct comparison if you want to think about type safety is if

A move from SPA means business logic moves to the backend and becomes hypermedia-driven, so the correct comparison if you want to think about type safety is if the backend server is type-safe. htmx is mostly declarative and its correct use could be statically checked with basic tools--it's not meant to contain complex logic.