AWS App Runner now supports Amazon Route 53 alias records for creating a root domain name. App Runner makes it easy for developers to quickly deploy containerized web applications and APIs to the cloud, at scale, and without having to manage infrastructure. When you create an App Runner service, by default, App Runner allocates a domain name to your service. If you have your own domain name, you can associate it to your App Runner service as a custom domain name. Now, you can use Amazon Route 53 alias record to create a root domain or subdomain for your App Runner service. For example, with alias records your App Runner service can now directly listen on example.com which was not possible with only CNAME record support which requires you to prepend a hostname such as acme.example.com.
Source:: Amazon AWS