simply use WordPress as the from name

start.sh

@@ -61,7 +61,7 @@ fi
 echo "Configuring smtp mail"
 $WP option update mailer smtp
 $WP option update mail_from ${MAIL_SMTP_USERNAME}@${MAIL_DOMAIN}
-$WP option update mail_from_name ${MAIL_SMTP_USERNAME}
+$WP option update mail_from_name WordPress
 $WP option update smtp_host ${MAIL_SMTP_SERVER}
 $WP option update smtp_port ${MAIL_SMTP_PORT}
 $WP option update smtp_auth false