Long running lambda functions are called AWS Batch. It’s a relatively unknown service but pretty decent if you need something like a GPU or long running jobs and can tolerate a 90 second cold start.
we even made an interface in code that runs a given task on a lambda (backed by a docker image) or batch (backed by the same docker image) depending on cpu/mem/time constraints. the tasks themselves also send a message when they're done so you can just subscribe to that vs. long polling.
