Unable to activate keyboard on my Apple Watch Ultra 2

Are you seeing this screen on your watch when trying to type?

If yes, tap on the scribble icon in the right corner to get back to the icons for all input options:

After that tap on the keyboard icon to bring up the keyboard.

And the watch should remember your input method for the next time.

To troubleshoot keyboard activation on your Apple Watch Ultra, consider these points:

• First, verify that your Apple Watch Ultra is running the latest watchOS software, as updates often include keyboard improvements.
• Ensure your iPhone and Apple Watch language settings are aligned and that your chosen language supports the Apple Watch keyboard.
• When in a text field, if the keyboard doesn't appear, tap the input method icon at the screen's bottom right to switch between Dictation, Scribble, and the Keyboard.
• A simple restart of both your Apple Watch Ultra and your paired iPhone can often resolve software glitches that might be preventing the keyboard from appearing.
• Also remember that there is an accessibility option for bluetooth keyboards, that is a seperate function from the on screen keyboard.
• If problems persist, consider unpairing and re-pairing your Apple Watch with your iPhone.

The keyboard is not available for all languages.

Enter text on Apple Watch - Apple Support

Try re-pairing your apple watch with iphone.

Make sure that on your iPhone in Settings/Notifications/Apple Watch ->Keyboard is disabled.