On the Result<TR, TE> responses... I've seen this a few times. I think it works well in Rust or other languages that don't have the ability to "throw" baked in. However, when you bolt it on to a language that implicitly can throw, you're now doing twice the work as you have to handle the explicit error result and integrated errors.

I worked in a C# codebase with Result responses all over the place, and it just really complicated every use case all around. Combined with Promises (TS) it's worse still.