iOS has an accessibility option called "Ignore Repeats", which seems like a better approach because it's system-wide. So people who need that kind of accommodation can have it in places like the on-screen keyboard too, without needing everyone else to slow down their typing.

That's good. I wonder if it should be opt-in instead of opt-out. Disabled people are arguably less able to find random configuration options than non-disabled counterparts. I get a bit bothered with how undiscoverable these options are. But power-users by their nature don't mind going to the extra mile to get perf out of their experiences.