You will still need to use an Azure Bot Service registration and Entra ID, which are both free. But if you want to host on AWS instead of an Azure App Service, you can do that.
We do not have any support for hosting in AWS - all of the provisioning (Bicep) files are setup for Azure.
The teamsapp.yml has actions in it that call the Bicep CLI which you could comment out or remove. Or you could replace with calling something like terraform and replace the infra/ files with terraform files.