In the past, there was a Communities module for this purpose. https://docs.adobe.com/content/help/en/experience-manager-64/communities/introduction/overview.html You need to research if this still exists.

Not following your issue. How do you want AEM to interact with S3? Sounds like you want an AEM Service to put objects into an S3 bucket. You state: " add objects to Amazon S3 bucket" If that is the case, why are you worrying about install folders? You should be looking at how to use the Amazon Java S3 API to interact with S3 from an OSGi service.

I would not depend on a Google report telling you 'How To' improve AEM performance.

You can look at using AWS Cloud Solutions in conjunction with AEM to build chat functionality. For example - https://aws.amazon.com/blogs/contact-center/reaching-more-customers-with-web-and-mobile-chat-on-amazon-connect/

You can add a custom solution - http://experience-aem.blogspot.com/2017/06/aem-63-touch-ui-rte-rich-text-editor-color-picker-plugin-inplace-dialog-edit.html

AEM does not support this functionality. You will need to build a new component.

Content Fragments are simply a collection of text and style. To build what you are describing, you will require a more complex set of components. You can look at using existing components or build your own components using Java and Sling Models.