mmm As of now, I think there isn't an official automatic batch checker tool provided by Google for RCS numbers. However, I understand that you can use APIs like Messente's Number Validation API, which can quickly and accurately validate phone numbers for RCS and a variety of other chat apps. For example:
curl -X GET
https://api.messente.com/v1/phonebook -u API_USERNAME:API_PASSWORD -d 'number=NUMBER_TO_CHECK&country=COUNTRY_OF_THE_NUM BER'
you would have to replace API_USERNAME and API_PASSWORD with your Messente API credentials, and NUMBER_TO_CHECK and COUNTRY_OF_THE_NUMBER with the respective information for the numbers you want to check.
*keep in mind that you will need to create an account with Messente and obtain an API key in order to use their API.
I recommend further research. Hope this helps u