Char Hi there!
I could be wrong, but it sounds like you're most likely running out of memory and this is why you're getting error.
If that's easy/possible for you, I'd recommend jumping into our Matrix rooms for help with installing GrapheneOS, as the chat is generally much more suited to helping with that kind of thing.
You can find links to those rooms here:
https://grapheneos.org/contact#community
Thanks!