one line, the multiline was not accepted, no clue why
mysql -u nextcloud -pnextcloud -Bse "SELECT CONCAT('ALTER TABLE \`', TABLE_NAME, '\`ROW_FORMAT=DYNAMIC;') FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_SCHEMA = 'nextcloud' AND ENGINE = 'InnoDB';" | mysql -u nextcloud -pnextcloud -D nextcloud