my iPad, 6 years old, will power up but I can't enter passcode as the login screen is unresponsive. I have tried reset unsuccessfully

If iPad isn’t responding, do one of the following:

• On an iPad with a Home button: Press and hold the top button and the Home button at the same time. When the Apple logo appears, release both buttons.
• On an iPad with Face ID: Press and quickly release the volume up button, press and quickly release the volume down button, then press and hold the top button. When the Apple logo appears, release the button.

If your iPad doesn’t 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.

If the second procedure, for a frozen iPad was also unsuccessful, you’ll need to seek assistance directly from Apple - either from Apple Support - or from the Genius Bar at an Apple Store.

You’ll find the Contact Support link at top-right of this page..

If you initiate contact with Apple Support using the link, they call you - so, no waiting “on-hold“.

Hello,

At any point was your iPad’s display replaced or removed (for a battery replacement)?