iPad ESIM Carrier Visibility

My iPad was previously used on AT&T network. Now when I go to Cellular Data, Add a New Plan, my only choice is AT&T and Other. T-Mobile was unable to set up my ESIM using Other. I contact AT&T advanced technical support twice. They did not know how to resolve for me. Please someone help me regarding Carrier visibility . All carriers need to show up on my ESIM.