I have a bulk email script ready which creates an email account and stores the credentials in a json file. Also, to validate the account creation, it logs into the account by using the credentials stored in the json file.
If you want, I can create another script through which you can enter the emails, passwords and the data will be written to the json file.
Removing the account creation part will make the script an email validating script.
Feel free to contact me for more details.
Thank you!