Hi @CONVERSO i have found the solution but I have run my system through GCP VM and also GCP Cloud DNS.
So you can just create a subdomain e.g https://botserver.mydomain.com then you point using google cloud dns with your rasa x ipv4 address. You can follow this youtube video that I have attached and scroll to 17:00 min for the cloud dns and at the same time if you would like to know how to set up the SSL cert do scroll to 16:00 min.