The build being "big" is rather vague. I'm assuming you've done the normal steps with moving as much as you can into CDNs, and not bundling unused JS, but there are limits to all tools. That in mind, this is more or less what Vercel was build for. NextJS is literally their framework, and assuming you are following best practice, its the right choice to use it for the hosting on your application (assuming financials etc). AWS amplify is fine, but like a lot of AWS tools, it suffers from being a general solution rather than a targeted one.
There are roughly 2 modes of use of Next.js: - SSG (Static Site Generation) that can be deployed with our tool at ScaleDynamics as a Hosting module: https://scaledynamics.com/static-assets-hosting - SSR ( Server Side Rendering), the most used mode in my opinion and which can be deployed with ScaleDynamics as a Server module: https://scaledynamics.com/managed-nodejs-server
Vercel does not support Docker, nor Dedicated servers, only Serverless. https://vercel.com/support/articles/does-vercel-support-docker-deployments
Vercel is quite vague on the available resources (sometimes GCP, sometimes AWS it changes over time ...) https://vercel.com/docs/concepts/edge-network/regions#routing
We advise you to look at our Scaledynamics offer as well, because we offer dedicated (not serverless). Moreover, you can choose the resource and the cloud provider and move at any time.