I'm not going to recommend anyone. I think plenty have already been recommended. Instead, I'm going to give my on requisites based-on what I want steemit to eventually be (a software platform).

Experience in

• Event sourcing
• Infrastructure as a service
• Command query request separation
• Graph theory and graph databases
• Golang and grpc
• Webassembly
• Serverless architecture design and implementation
• Concurrent (not multithreaded) programming
• Openapi
• Cryptography
• Penetration testing
• Load testing
• TICK stack, monitoring systems, and user analytics

Get someone that knows that, and you'll be set. My $0.02