The iOS 26.4 update that Apple plans to release as soon as next week includes improvements for the built-in iOS keyboard. In its notes for the software, Apple says iOS 26.4 offers "improved keyboard accuracy when typing quickly". There was a bug in iOS that caused some characters to be missed when a user was typing quickly. The character appeared to be tapped in the keyboard, but was ultimately not inserted.
That could be part of it. The iOS keyboard has swipe type now, and it’s been kinda shitty at touch typing since around the same time.
Yeah, I turned off swipe right away since it thought I was swiping. Then noticed the problem above.