IPad Pro 11 Performance Issues

If exchanged under an active AppleCare plan, Apple may exchange your iPad for a renewed/reconditioned iPad of the same model and specification as the iPad that you have now.

Given the troubleshooting already attempted, your next step would be to fully reset your iPad - restoring your data from your iCloud or iTunes backup - ensuring that your backup is as up to date as possible before performing the reset:

How to back up your iPhone, iPad, and iPod touch - Apple Support

When you are happy to proceed, you can perform the reset from iPad settings:

Settings > General > Transfer or Reset iPad > Erase All Content & Settings

After resetting, you’ll set-up the iPad “as new” from the initial “hello” screen. At the end of the process, you’ll have opportunity to restore your backup to the iPad.

You’re very welcome.

Hopefully the reset will restore normal function; a full reset and test, prior to exploring alternative remedies, would be the most sensible avenue to pursue.

As for Apple’s own renewed/reconditioned devices (as opposed to reconditioned devices that may be offered for purchase via non-Apple retailers), these are reportedly indistinguishable from new - having passed Apple’s own Quality and functional testing - and having a new casing and battery.