You could always use an ALB? ALB has some nice extensions as well.
Definitely cheaper than API gateways for even a moderate amount of traffic, but API gateway costs scale down to zero for unused or rarely used endpoints.
Note: The “official” way to work around this is to write your large payload to S3 and then create a pre-signed S3 URL that you return to the caller instead.
ALB with Lambda - 1MB
Lambda - 6MB
https://docs.aws.amazon.com/elasticloadbalancing/latest/appl...