Hey Jovan! I haven't used gRPC, but I have heard of it and know a little bit about it. gRCP is a different project with different goals than tRPC.

tRPC offers a more "traditional" client-server architecture (Can use Next or normal React with Express), while gRPC seems better suited for things like microservices/systems. To me it's not a case of reinventing the wheel, but instead picking the right tool for the job.