How to REMOVE the keyboard from my Apple Watch 5

Force Close the Messages App, then open it again. To Force Close apps on Apple Watch, press the elongated power button, which will bring tiles showing the apps you've used most recently. Slide to the right (or left) until you see an X and tap the X to Force Close it.

If that doesn't help, restart your Apple Watch. Press and hold the elongated power button until you see a power icon in the upper right hand of the screen. Tap the power icon, the swipe to power off. Wait a minute, then power the watch back on, sign in and see if you read your messages.

I've owned Apple Watch for a long long long time. I don't ever recall seeing text messages grouped by date of arrival. On Apple Watch, you've always had to manage messages on the watch itself. And deleting a message on your watch, will not delete it from any of your other devices. Just like deleting a message on your iPhone, won't remove it from your watch. It's just how WatchOS has always managed messaging on Apple Watch.

In terms of not updating, you can certainly turn off automatic updates and choose to never update your watch, but that would be a very bad choice. Updates do bring new features, but more importantly, they bring security updates, which are essential to keeping you and your watch data safe.

I don't believe you can remove the keyboard. You can use the Microphone instead if you'd prefer to dictate a response. Or you can scribble as opposed to typing on the keyboard.