Write something that sounds fun. It doesn't even have to be useful to anyone, just interesting. And you have to be able to talk about it. The last person we hired for our team, I actively courted because he'd written a javascript parser (note: just a parser, it parsed basic JS to an AST and did nothing with it) and talked about it at a local rust meetup I'd been hosting (until COVID).

If you don't have local (or maybe now vitual?) meetups to go to, write a blog post about it and post it to HN and put a single sentence "I'm looking for a job that lets me write Rust professionally" note at the bottom, you never know who's going to see it.