The GP-7 only comes in size L, correct. The XL shell is larger than the L so there is no way to put XL padding into an L. Plus, the GP-7 interior is different shape than the 6, so a GP-6 interior won’t even fit in a 7 I don’t think. Also Arai interior is glued in and not removable.
The new helmet models will come out in the fall of 2025 but I’m not sure how they will handle the XL size or if Arai is making a totally new model. Arai has had stocking issues lately which I suspect is them getting ride of 2020 stock in preparation for 2025 models.