Was it a DSG or manual?
I’m asking because we do have the 1.5 TSI DSG in our Ateca, and i’ve never felt “undermotorised”. Could always be more of course, but it pulls adequately in all ranges, 0-60 with only me in it in 8.4 seconds. Not blisteringly fast, but certainly sufficient. Upside of course, if i don’t put my foot through the floor, tops out at 50mpg which is very reasonable for a “SUV” with 150hp auto.
Not driven a T-Roc, so i wouldn’t know what the issue was there, but i’m surprised by the vehemence you declare it too slow. Makes me wonder if something was wrong with it, or if it has to do with the update 2 years ago where the engine management was updated to reduce the endemic problems with that engine (flat spot in 2nd gear, but only a problem in manuals).