Order books for the mk8.5 (non-performance models) only opened last Thursday (11th April), so probably a bit early to ask that question.
As for the GTI and R performance models; based on previous Golf new model and facelift launches, I’d anticipate order books for the GTI and R won’t open until Q3, with the first deliveries of GTI’s and R’s probably late Q4 2024 / early Q5 2025.
Currently, only the Life, Match and Style models are available to configure on the VW UK website. Assume the R Line (and GTE?) will be added in due course.