Same problem experienced, charger changed, tried reset, no joy.
Cleaned out the charging port with IPA solvent and toothbrush (showed signs of some arcing may have occurred), still wouldn’t charge though apple logo would come up and home page but no charge symbol in battery.
Decided to spray charge port with IPA and long soak, approx 1 hour.
Result, charging away quite happily.
If it works for you too then suggest remove USB from plug first iPad last.