Generally speaking, the available options are listed here: https://learn.microsoft.com/en-us/defender-office-365/create-block-sender-lists-in-office-365
Note that most of these require admin privileges. Also note that Microsoft's recommendation is to set the SCL (spam confidence level) for such messages, which might indeed result in quarantining them, instead of outright blocking the delivery. Probably the easiest way to address this is to create a transport rule with the "block the message" action, instead of the recommended "Set SCL" one.