If you want to prevent the formation of a pool of cheap exploitable immigrant labor, there are two ways. The best would be to prevent immigrants from entering, but that's impossible. The second best is to make sure that those who enter have the same freedoms and protections as native born workers, so that unscrupulous employers can't take advantage of them (house cleaners paid below minimum wage, H-1B tech employees paid under the table, chicken processing plants [0]).

0: https://www.washingtonpost.com/outlook/2019/08/09/poultry-in...