Create groups for your users and give those groups access to the dataset

Integrate with a single sign-on (SSO) platform, and pass each user's credentials along with the query request

Create a service account and grant dataset access to that account. Use the service account's private key to access the dataset

Create a dummy user and grant dataset access to that user. Store the username and password for that user in a file on the files system, and use those credentials to access the BigQuery dataset