Should we switch the default Lambda architecture?

Lambda architecture can either be `x86_64` (default) or `arm64`. The Arm architecture [can be more cost effective](https://aws.amazon.com/blogs/aws/aws-lambda-functions-powered-by-aws-graviton2-processor-run-your-functions-on-arm-and-get-up-to-34-better-price-performance/). We should investigate this and determine whether it makes sense to switch to Arm by default.