Whether or not his administration managed to cut back on illegal crossings (mainly ICE raids I would guess), he definitely and dramatically did cut back on legal visas offered. Thus farmers, who relied heavily upon those with temporary work visas, panicked there during the first year of his administration, e.g. https://www.nytimes.com/2017/02/09/us/california-farmers-backed-trump-but-now-fear-losing-field-workers.html.

If conservatives really wanted to stop illegal immigration, they would go after the employers who hire them

Conservatives never really want to accomplish most of their stated goals - it's like a dog chasing after a car, they wouldn't know what to do if they ever caught it. The catch is that Trump isn't actually conservative, he simply used those talking points, too dumb to realize that he wasn't supposed to mean any of it:-P.

He also wasn't Republican either, although there he won, since he hollowed out the Republican party, laid his eggs inside its brain and now he controls the corpse. I think McCarthy was the last vestige of a Tea Party style fiscal conservative, and now the Alt Right has taken complete control, even as they already have started eating their own and demolishing that from the inside with an even more hardcore line, where e.g. the infamously extreme Fox News is no longer extreme enough.

But anyway, yeah if they truly wanted to stop immigration that is what would need to be done, but they don't be it's such an easy talking point that they've invested so much effort into, they can't afford to lose out on it now by actually solving the damn thing!:-P