There was no method to clear all the rows of a repeater ... This is a new Field prototype method

Add an empty method to ACF Repeater

  /**
     * empty function for acf.Field ie, it clears all the existing rows
     *
     * Only for repeater
     *
     * @returns {boolean}
     *
     * @author     : Christian Denat
     * @email      : [email protected] / [email protected]
     *
     * @date       : 20210526
     *
     */
    acf.Field.prototype.empty = function() {
        if ('repeater' !== this.type) { 
            return false;
        }
        this.$('tbody:first tr:not(.acf-clone)').empty();
    }