Hey I run a consultancy that helps solve exactly this kind of problem. Our main business is connecting open source freelancers with companies, but we've often see this use case where a company has a specific open source need and we help facilitate this. Let me know if you want to chat more - we could take over everything and we take a 10% cut. This is us: https://www.hydraoss.io/
Hey we would be happy to take this on at Hydra (https://hydraoss.io/). We're an agency built for this kind of problem - finding people to fix things in open source. In contrast to a bug bounty program, we manage everything end to end, and the customer just pays us the invoice and doesn't have to deal with anything else. We specialize in Rust but we've had customers from everywhere. Let us know!
Hey thanks for reading, I'm the author of the piece. The original went through a couple rounds of edits since it's on the company page but PM if you want the original :)