It's possible for immigrants to both increase the health of the economy in the medium to long term and to cause localized economic pain in the short term. For those living paycheque to paycheque it's the short term that matters because they don't have the luxury to wait for the longer term effects to play out.

I say this kindly, you must have never worked a labor-intensive job and watched your friends(co-workers) get laid off for cheaper labor.

This happens regardless. Either the factories go to different countries or the cheaper labor is imported. There's not really a way to prevent this.

Hmm, tariffs and closed borders might.

I am not saying I endorse either thing, just answering your "not possible" claim. Most things are possible, few things are not.