Just one question. I see all these 3rd party clients solving the problem separately. Isn't it easier for everyone to build a unified decoder backend that exposes a stable and consistent interface for all the frontends? That way, it will get more attention and each modification will have to be done only once.

Since JS is the big issue here, the backend itself could be written in JS, TS or something else that compiles to WASM. That way, the decoder doesn't have to be split between two separate codebase. Deno also allows the bundle to be optionally compiled into a native executable that can run without having to install Deno separately.

Alternatively, I'm not sure if this might be an impetus to move the bulk of the codebase itself to TS/JS and just use Deno/Node/Bun or otherwise to move to Rust with rusty_v8 or deno_core directly.

You mean, like the yt-dlp-ejs package?