using amazon sns to send message to end user for transactional services

Hi, We have to send text sms to our end user using amazon aws sns service. as of now we are using Twilio but we want to use one more service for it. I have created account in aws and sent message to my mobile number and it is getting delivered so prototype is done but now the questions is:-

1. Does aws support MTLS. As per my organization if we are interacting with any third party service then authentication should happen using MTLS. as far as I know aws sdk uses TLS 1.2 . will this customization be possible? or any work around or any other security mechanism we can use? instead of sdk can we use rest end point to send message?

2. I am not able to check DR of my message. so when I read documentation I found I need to use cloud watch for it.

basically We are not using AWS as of now. Our java spring boot application is hosted in PCF. is it possible to use only amazon sns without other service of AWS for my requirement? if not which all service we will have to use? also is there a facility in AWS SNS through which it can send delivery receipt of the message or does it provide any rest end point which which we can call? We have traffic of more than 2 million a month so want to know in great detail.

MTLS is mandatory. I read amazon APIGW support MTLS but we dont want to use it until no option, you can explain this flow as well. if this flow works then my application will send sms to my apigw which will send to aws apigw and then mesaage will go to sns. till aws apigw communication will happen using MTLS. Please correct me if my understading is incorrect.

Thanks in advance. Rohit