Using AWS Lambda as SSR in Quasar may not work out of the box, spent some time getting Quasar app set up in AWS Lambda. Turn out I used serverless framework to get them to integrate.
I have written a short article in medium to showcase!
https://medium.com/@me.gordonlam.space/use-serverless-to-serve-your-server-side-rendering-project-vue-quasar-d40447225a4f
I hope it helps! Enjoy!