iOS 26 on iPhone 15 Plus: Keyboard frequent typos & input lag (iMessage, WhatsApp, etc.)

Details:

After updating to iOS 26.0 on iPhone 15 Plus, the default Apple keyboard became less responsive: frequent typos, over-aggressive autocorrections, and noticeable input lag when typing fast. This occurs not only in iMessage but also in WhatsApp, Notes, Mail, Safari, and other apps.

Device & Software: iPhone 15 Plus, iOS 26.0 (latest), Apple keyboard (Indonesian & English), no third-party keyboards.

Repro: open a chat app → type a fast, mixed-language paragraph → observe swapped/missing characters, incorrect autocorrections, and delay.

Expected: responsive keyboard with accurate predictions, no lag.

Actual: typos, wrong replacements, and input lag—especially when switching languages.

Tried: restart; latest iOS; toggle Auto-Correction/Predictive/Smart Punctuation; reset keyboard dictionary; disable haptics; free storage (>10 GB); Reset All Settings; reproduced across Apple & third-party apps.

Ask: Is this a known iOS 26 issue on iPhone 15 Plus? Any diagnostic profile I can install to capture logs? Please consider a fix in the next update.