Don't switch unless your actual metrics show a problem. I've seen teams burn cycles chasing runtime performance on hobby projects that spend 99% of time waiting on DynamoDB or API calls anyway.
Bun's value is real for specific things: CLI tools, bundling, local dev experience. But for Lambda workloads, Node's cold start tax was overblown by mid-2023. The ecosystem maturity gap still exists. Stick with what you know unless you're optimizing for something concrete, not hype.