Heya! Creator of tRPC here, just wanted to drop by and say thanks for all the love ♥
I quite remember tRPC being the only unknown part of the stack when I started there, and I was a bit scared, but tbh it was pretty easy to pick up and it's an awesome abstraction to make the server of fullstack codebases in typescript.
I always liked GraphQL but if you're working solo it doesn't make that much sense to have the GraphQL api as contract. With external devs a little bit more.
+1 to OpenAPI and being able to generate code, SDK's, docs, automagically.