If you’re seeing this error after setting up a database and user:
PDOException: SQLSTATE[HY000]  The server requested authentication method unknown to the client
If you’re setting up WordPress and the installation is unable to connect to the database.
ALTER USER 'username'@'localhost' IDENTIFIED WITH mysql_native_password BY 'p@s$w0rdHere';
Run above prior to reinstalling MYSQL or other complex attempts at a fix.