Sure. Write a Roslyn analyzer to help out here.

Note: it's not like you can just sprinkle 'ref' on the return type of your methods willy nilly. Like 'ref'/'out' parameters, it requires you to do very specific things to keep your code safe/legal. As such, it's unlikely to just be added by people because, by and large, most code won't be equipped to actually handle it properly.

The codebases that will want to use this are already ones that have done a lot of work that makes them amenable to ref. i.e. game engines where you have large arrays of structs that you want to operate on in an efficient manner and whatnot.