Two people from the Rust team have posted about their situation, one was laid off and one was not. Unsure about the others. Many of the Servo folks (and possibly all, it's not 100% clear yet but it doesn't look good) have been laid off.
The vast majority of contributors and team members are non-Mozilla, though the Mozilla folk are very important. Rust will survive. This situation is very painful, and it has the possibility of being more so, but (thanks to a lot of work from people (not speaking of myself here) who used to be at Mozilla!) Rust is bigger than Mozilla, and has been on a long road towards diversification. Some other companies have stepped up to pay a bunch of the bills that Mozilla used to pay, namely Amazon and Microsoft. Here's hoping that we get even more involvement in the future.
Anyway, two big projects in a similar space to QEMU are Firecracker (the underlying virtualization tech for AWS Lambda + Fargate), and Crostini (the underlying virtualization tech for ChromeOS). Firecracker started life as a fork of Crostini and now there's a rich ecosystem going on in this space.
Don't forget the Rust code from Servo that lives in Firefox, too.
Yeah, it's tough to get the combo of all of those things, for other reasons too. I would probably want to first reach for VS: Code, which uses ripgrep for search. But that's a "important component written in Rust", rather than a whole-Rust project. There's tons of tools like ripgrep, which is the most well-known, but it's hard to say how popular they are. And there are things like 1password, which do run on people's machines, but aren't open source.
I actually have recently seen a bug report that implies something really, really huge in this space, but I don't want to jinx it, so I'm not gonna link just yet. We'll see :)
If widely-used doesn't imply open source then there's a lot of options. Dropbox use Rust in their sync client, as well as in their storage backend. Cloudflare are using it for their VPN. Microsoft are rewriting parts of windows in it. Amazon are using it for their Firecracker micro-vms that power lambda.