iPad Pro screen is multicoloured fuzzy lines

As described, your iPad may have a hardware fault - or its battery may have reached the end of its usable life. If the battery has failed or is failing, the iPad may unexpectedly turn-off - or may not successfully boot to a running state even when connected to its Power Adapter.

Are you able to use the iPad while remaining connected to your Power Adapter? If yes, while monitoring the indicated battery state, disconnect the Power Adapter; if the indicated battery state suddenly falls, or the iPad shuts-off, this test demonstrates the iPad battery having reached the end of its usable life:

iPad Repair & Service - Apple Support

Otherwise, see >>> If your iOS or iPadOS device restarts or displays the Apple logo or a spinning gear unexpectedly - Apple Support

If your iPad is unresponsive, connect your iPad to its Power Adapter and allow the iPad to charge undisturbed for at least an hour, or preferably overnight. Then, while still connected to external power, try a forced-restart:

Force restart iPad (models with Face ID or with Touch ID in the top button)

If your iPad doesn’t have the Home button, do the following:

1. Press and quickly release the volume button nearest to the top button.
2. Press and quickly release the volume button farthest from the top button.
3. Press and hold the top button.
4. When the Apple logo appears, release the top button.

Force restart iPad (models with the Home button)

Press and hold the top button and the Home button at the same time. When the Apple logo appears, release both buttons.

If iPad still doesn’t successfully turn on, or if it gets stuck during start up, see the Apple Support article If your iPhone, iPad, or iPod touch won’t turn on or is frozen. Or if your iPad isn’t working correctly after you restart it, see the iPad Support website.

If you continue to experience difficulties, you would be best advised to visit the Genius Bar at your local Apple Store or Apple Authorised Service Provider (AASP) - where the technicians will be able to test and assess your iPad:

Genius Bar Reservation and Apple Support Options - Apple

A correct diagnosis 🙂

Should you choose to do so, Apple offers a fixed-price price battery replacement service. You can verify eligibility and cost for your region/country here:

iPad Repair & Service - Apple Support

For practical purposes, in lieu of replacing the battery and returning your own iPad, Apple usually exchange the iPad for a renewed/refurbished iPad of the same model and specification. The cost of the exchange is the same as would otherwise be charged for the battery change. The cost of a replacement battery will be considerably less than the cost of purchasing a new iPad.

If you have an active AppleCare+ plan, the cost will be reduced to a small excess/deductible fee.