How to reliably listen for Hedera HCS messages in a Next.js Edge runtime?

I'm building a real-time feed for my dApp using Hedera Consensus Service (HCS). My backend is running entirely on Next.js Edge functions on Vercel.

However, the official @hashgraph/sdk uses long-polling/gRPC connections that constantly time out or violently drop in Edge environments. Does anyone have a reliable architecture or work-around to stream HCS messages in a Serverless context without connection drops?