Why can’t I split the keyboard on my new iPad Pro 3rd generation? This is extremely frustrating!

The Split Keyboard is not supported by any iPad with a screen size greater than 10.5”. As such, all 11” and 12.9” models of iPad Pro - and the new fourth generation 10.9” (or later models) of iPad Air do not support the Split Keyboard. These models support the new Floating Keyboard in addition to the standard Full-size on-screen keyboard.

All other models of iPad (including the 9.7” and 10.5” iPad Pro) - running iPadOS 14.x - continue to support the Full Keyboard, Split Keyboard and the new [small] Floating Keyboard.

Use the floating keyboard on your iPad – Apple Support

Split and move the keyboard on your iPad – Apple Support

I believe Apple replaced the split keyboard for a smaller floating one that can be placed anywhere within the iPad's screen.

Sorry.

You can, directly, send unacknowledged feedback about this missing feature to Apple below.

Tap the link below.

Feedback - iPad - Apple

Best of Luck to You.