GGGG I think it may be useful to keep in mind that at present no version of the code exists without the write-after-free bug. Clearly Samsung and Google are not running that code in an environment that detects the bug, and it can be fixed only by them. Since there isn't a way for the GrapheneOS project to solve the problem, and there are many issues they can solve by spending time, time might be spent on those issues.
My understanding is that Google plans to, over time, run more code under MTE, but I think vendor code is not at the forefront, which is unfortunate but unsurprising. There is so much code out there with bugs in this class.
Perhaps an enterprising bounty hunter might demonstrate a crash or a vulnerability based on knowing there is a UAF in this module, which might turn up the heat on Google and Samsung, or perhaps a very enterprising tech journalist might write about it.