Since you are collecting small amounts of data, an option could be to write your package of data into SQS.

A periodic lambda or EC2 could empty the SQS queue data into a DB or whatever you required, at an interval to amortise cost of running - say every 30 minutes, depending on your traffic: make timing adjustable by parameter !

If you are concerned about runtime, set up boto3 handles etc in the lambda init so they get reused rather than being recreated each time.