I’m not sure that this comparison is valid. You got a brand new top spec hot PHEV Golf on one hand, with all the new toys like matrix LED units etc, and a mid spec end of life T-Roc (with a facelift confirmed in march, release around q4 this year where it will get the fresh infotainment, probably matrix LEDs as well, and potentially a 48v hybrid too).
The price for the GTE is fair (ish), the only Golf with an outlandish price tag is the Golf Style eTSI for £2800.
That said: the GTD just blows all the things out of the water, in terms of value for money, at £1800 for the GTD, there’s no beating that.