You can simply DYOR to avoid possible scams.
https://www.toptal.com/blockchain

There are a lot of companies now where you can find a good developer, choose a legitimate one to always assure a good developer not a scammer.
Based on my small research, here's what I've got.

• https://whitecodelabs.com/
• https://blockchain-solutions.tech/
• https://www.netobjex.com/

Anyway, good luck with your project.