Trump engineered the gerrymandering of the House through a pressure campaign, and after Callais, no fewer than eight states redrew their maps in his favor that experts estimate should pick up 10 to 12 seats overall, while another estimate says they could gain as many as 16 to 18 seats if all the aggressive redraws were to fully materialize. Link
I don't know what the benchmark would have to be for you to acknowledge it as a success, and maybe it can be argued that he did not get a 100% uptake rate on the re-draws, and there may be some way it all still falls flat for him in November. But at this point, I don't believe it can be reasonably argued that he did not succeed in his quest to engineer a gerrymandering of the House.