ionic-framework: bug: scroll assist needs improved keyboard estimation on web

Prequisites

• I have read the Contributing Guidelines.
• I agree to follow the Code of Conduct.
• I have searched for existing issues that already report this problem, without success.

Ionic Framework Version

• v4.x
• v5.x
• v6.x

Current Behavior

On iOS Safari (and as an app with “Add to Home Screen”), there is an uncomfortable pause when switching between inputs.

Expected Behavior

When tapping another input on the page to switch focus, there should be no delay when no scrolling is required and keyboard remains open.

Steps to Reproduce

1. Open following app in Safari on iOS/iPadOS device or simulator:
   • with “Device Preview” QR-code on https://dashboard.ionicframework.com/preview/f7e6e842/mbb6khxjl9
   • or directly at https://mbb6khxjl9.appflowapp.com/
2. tap “Address Line 1”
   • caret appears at the beginning of Address Line 1
   • keyboard shows up
3. tap “Address Line 2”
   • caret disappears from “Address Line 1”
   • keyboard stays open
   • – awkward pause lasting about a second –
   • caret appears at the beginning of Address Line 2

reproducible on:

• iPad Air 2 (iPadOS 14.6)
• iPhone 12 mini (iOS 14.4; on Simulator)

Code Reproduction URL

https://github.com/ippeiukai/ionic-safari-input-issue-23664

Ionic Info

$ ionic info

Ionic:

   Ionic CLI                     : 5.4.16 (/■■■■■■■/lib/node_modules/ionic)
   Ionic Framework               : @ionic/angular 5.6.11
   @angular-devkit/build-angular : 12.1.2
   @angular-devkit/schematics    : 12.1.2
   @angular/cli                  : 12.1.2
   @ionic/angular-toolkit        : 4.0.0

Capacitor:

   Capacitor CLI   : 3.1.1
   @capacitor/core : 3.1.1

Utility:

   cordova-res : not installed
   native-run  : 1.4.0

System:

   NodeJS : v12.22.3 (/■■■■■■■/bin/node)
   npm    : 6.14.13
   OS     : macOS Catalina


  ────────────────────────────────────────────────────────────

          Ionic CLI update available: 5.4.16 → 6.11.8
                                
     The package name has changed from ionic to @ionic/cli!
                                
             To update, run: npm uninstall -g ionic
                 Then run: npm i -g @ionic/cli

  ────────────────────────────────────────────────────────────

Additional Information

Observing the DOM with Web Inspector suggests the relocateInput hack is being executed when “Address Line 2” is tapped, although there is no scrolling happening and the keyboard is already open and remains open. https://github.com/ionic-team/ionic-framework/blob/v5.6.11/core/src/utils/input-shims/hacks/common.ts#L14

Our production app (which uses @ionic/angular 5.3.3) is affected and one of the views has severely degraded user experience as a result. Any help or workaround would be greatly appreciated.