Lightsail in stream theme (Wordpress)

Hello.

Problem 1: I want to share my broadcast load with Amazon while the live broadcast is on.

In general, I think it's a good idea to set up a CDN before Lightsail.
For example, if you are using AWS, you can use CloudFront.
In addition, CloudFront can also be used together with AWS Media Services, so you can collaborate when performing live distribution using AWS Media Services in the future.
https://docs.aws.amazon.com/AmazonCloudFront/latest/DeveloperGuide/Introduction.html
https://docs.aws.amazon.com/AmazonCloudFront/latest/DeveloperGuide/IntroductionUseCases.html#IntroductionUseCasesStreaming

Problem 2: I want to store the videos uploaded by users on Amazon. How can I do it?

Video files and the like are often stored in S3.
https://docs.aws.amazon.com/AmazonS3/latest/userguide/Welcome.html