"Too many redirects" error for some users

Doesn't sound DNS-related. Probably something in either your web server or your Wordpress configuration.

Hello,

The error "Too many redirects" occurs when your website is stuck in a redirect loop. Kindly check your server configuration for any redirection rules that could result in a loop.

The error could also be caused due to an HTML/PHP/JS page which redirects to another page which inturn redirects again to previous page

The redirection configuration will need to be done on the server itself. Route 53 is a DNS service and it only resolves your Domain name and returns the IP address of your server.

The "Some users" makes this a bit confusing. Agreed that this is likely something either in the httpd/nginx config or in the application. A common scenario is http-->https redirects when dealing with a load balancer, and not having the traffic flow/apache configs setup correctly.

Are you restricting the /admin page to specific subnets/ips..e.g. based on whether they are on a vpn or not? that would also (likely) be something in the apache config somewhere.