Graphql is a protocol for interacting with a remote system, parquet is about having a local file that you can index and retrieve data from in a more efficient way. It’s especially useful when the data has a fairly well defined structure but may be large enough that you can’t or don’t want to bring it all into memory. They’re similar concepts, but different applications

The market isn’t great right now, and a lot of companies are doing the thing where they list jobs just to make their teams feel like more help is coming, but have no intention of hiring for the role. Try not to take it personally when an application doesn’t work out, it usually is more about them than you, and the numbers game works against you. Hang in there, you’ll pull through if you keep at it