Here's the current tech stack of this site:
Hosting: Google Cloud (Cloud Run, Cloud Storage)
Database: Postgres
Sessions, caching (not implemented yet): Redis
Backend: Node.js with TypeGraphQL, TypeORM
Frontend: Next.js, React.js, Apollo GraphQL, TailwindCSS
Ethereum: ethers.js, hardhat (not implemented yet)
Once the features I want to build are finished, I'll start moving things to IPFS and Arweave. For full decentralization may consider Ceramic. But my priority now is getting all the core features implemented first before going full decentralization. The main problem with decentralized webdev now is immaturity in the ecosystem (which I wrote about here) and performance.
I didn't pick this stack because I think it's superior to others, I picked it just because it's what I'm most familiar with, and thus what I can develop the fastest in. Tech stack really isn't the highest priority for an early stage startup because the primary goal for a startup is getting product-market fit.
Once things are production-ready and in a good enough state, will move to open source. In the meantime if you're interested in working on this, just comment here and/or shoot me a message and I'll get you access.