JS/TS has

    y = { ...x, change: 'b' }

And Swift avoids the mutability-problem all together, by providing structs with copy-on-write and self-mutating methods:

https://docs.swift.org/swift-book/documentation/the-swift-pr...

I think C# borrowed this feature from functional languages like Haskell or OCaml.

I would credit F# even more. It's been a main source of new C# features for a while now.

From F#, most likely! C# converges more and more on F# with every release.