DeletedUser19 None of those links have anything to do with removing SIM Toolkit.
Indeed. My claim was "disabling or deleting some GrapheneOS system app", not "deleting SIM Toolkit". There are a lot of system apps, and so far there isn't a giant list of whether it's ok or not-ok to delete each individual one. Maybe it's ok to delete the SIM Toolkit for all users, maybe it's ok for users of some carriers, and maybe for some users it would be fine for a month and then not.
If you do go ahead and delete it, there may well be people interested in hearing about your experience. If you are comfortable indicating which carrier that experience relates to, that may well be of interest as well.