> But it strangely leaves open the possibility, without saying either way, that a longer iv, with r(i)>96 random bits might allow generating more iv's. As you point out, it will depend on the properties of GHASH (and potentially on how the result is used downstream from there).
There is some details on the "GHASH as initial counter value" which seem to suggest that for larger nonces, the total number of messages shouldn't exceed 2^44.5 here: https://neilmadden.blog/2024/05/23/galois-counter-mode-and-r...