Brightness widget not working after 18.6.2 update on iPhone 13 Pro

It's not always the iOS update's fault!  Many things can cause phone problems.  If you tell people you think it's an iOS update, it might make it harder to fix or find a solution for the real issue.

Remember, the right question often leads to the solution!

Was/Is your device Jailbroken? If that's the situation, please be informed that attributing the issues to iOS updates may not be accurate.

iOS updates aim to enhance user experience, boost security, and fix bugs rather than disrupt core features. The majority of the issues after updates might stem from underlying, unmentioned factors. Updates won't typically alter personal data but may refine settings or features. Backup before major updates for safety. Review Apple's update details and backup advice for a smooth process.

Kindly consider checking your settings and addressing any device issues before attributing the issue to external factors. This could be a pure coincidence that the iOS update affected the iPhone functions.

Before initiating a standard iOS update, it's advisable to create a backup. Have you completed this step? If yes, proceed with the restoration from the backup.

See what each update does: About iOS 18 Updates, About iOS 17 Updates, About iOS 16 Updates, About iOS 15 Updates, About iOS 14 Updates, About iOS 13 Updates, About iOS 12 Updates, and so on...

Brightness can be adjusted through Control Center (the sun slider) or via Settings → Display & Brightness.

I have not come across a standalone widget for brightness that you can place on the Home Screen or Today View.

The closest you get is:

• Control Center shortcut (always available with a swipe).
• AssistiveTouch custom actions (you can assign brightness adjustment).
• Shortcuts app automation (e.g., tapping an icon to set brightness to a certain level).

So, a true “widget for brightness” is indeed unheard of on iPhone.

Have you checked if the last option "autobrightness" (at the very bottom in Settings>Accessibility>Display & Text Size) is enabled?