As far as I can see, as @LostKobrakai said, this cannot be achieved with macros, because it is not valid Elixir syntax. You would have to build a transpiler, but that’s a totally different kind of problem.
I’d suggest using one of the typing solutions proposed. The issue is mostly about familiarity, and it will soon become second nature if you use it a lot.
My personal view is that a syntax like MyStruct my_var = Module.some_function() would lead people to (erroneously) assume that this is a static type check, while %MyStruct{} = ... makes it clear this is a pattern match, which usually is amongst the first concepts learned when approaching Elixir. In fact, in many cases, when needing to access fields in the struct, one would directly do %MyStruct{ my_field: x } = ....
In other words, there is a trade off between ergonomics and consistency/parsimony of the syntax. Some alternative way to express the same construct more concisely might save some keystrokes, but it adds to the cognitive load of having to understand different ways to express the same thing.
