I have worked for some time with Next.js and SST / OpenNext. I think that if you are fully into the AWS ecosystem OpenNext is a great option; although you have to take into account that there may be some compatibility issues with the new features mainly. If this is a big concern, I think both Remix and Astro are a great option because of the adapters. I have been using Astro for my personal blog and I love with its simplicity. My impression is that it could be a good option even for big projects.