As a data engineer, you are tasked with creating a data pipeline to load CSV files from Google Cloud Storage to BigQuery. However, these CSV files are known to have multiple data quality issues. Specifically, the files contain columns with mismatched data types, such as a mixture of STRING and INT64 values, and inconsistencies in the formatting of certain values, including phone numbers and addresses. Your objective is to ensure the data maintains high quality by performing the necessary cleansing and transformations during the loading process. What steps should you take to achieve this?