ReScript is excellent. Same type system as ocaml, which is IMO the sweet spot between power and straightforwardness. You lose the "you can represent ANYTHING" capability of TS which is both a pro and a con. In exchange it's much simpler to work with and has excellent type inference for day to day work.
The externals binding system for JS libs works well for integrating libraries. And react bindings are included in the standard lib, they also work great. The compiler is fast and produces generally quite reasonable JS.
You could argue that it's not "better" than elm in a theoretical sense. But for practical work it's much closer to the mainstream of web dev in mindset and syntax. Easier to learn, much easier to integrate with other frameworks or into existing teams & codebases. And it's less opinionated about rendering: the tooling generally assumes you're using react, but you don't have to and it can emit anything if you do some extra work wiring it up. I have used it with node and even, irresponsibly, deno fresh.
Been using it whenever I can for frontend stuff for a year now and haven't enjoyed a language this much since... well... elixir.
Purescript has by far the strongest type system of any mature compile-to-js language, good FFI, footprint comparable to react.
Elm is a heavily stripped down purescript, plus an ambiguously-benevolent dictator for life. Also truly terrible interop. It's a good learning environment but I would strongly recommend against using it for anything big.
Rescript is basically Ocaml with half-js syntax.
Typescript is bizarre. On a scale from 0 (C) to 10 (Haskell), it's a 12, a 6, and a 2 duct taped together. It's got some incredibly powerful features (template literals, conditional types), but it's missing most of the standard "advanced"-but-production-ready type system features (e.g. no HKTs, no type-directed emit) and the foundation is absolutely riddled with soundness holes.
Yeah, that's what I meant by "mature". Agda also has a js backend, but neither one can really stand alone. Haskell is closer, but GHCJS is still very much a second class citizen of the ecosystem.
Clean also has WASM as the compile target via its IR, and its tooling is great. Unfortunately though I couldn't find any sort of a community when I was looking into it, but other than this the language looks quite mature and very industry-oriented.
Then there's Lean which also can compile to WASM via some sort of a bridge, it has decent tooling but the ecosystem is still nonexistent.
Typescript's unsoundness isn't a good thing, but it is way down the list of type-unsafe things inherent in the Boschian nightmare that is frontend development.
Compile-to-JS languages add a big impedance mismatch when you inevitably need to use JS libs. Typescript's JS + types philosophy helps with this issue (it still sucks though).
