Doesn’t show charging or turn on

This iPad was previously working but had a cracked screen. It sat for a few weeks without being charged. I plugged it in and the battery icon did not appear. I knew the lightning connector was worn out. I ordered a new screen and lightning connector. I successfully replaced both. It still will not charge or turn on. I decided to replace the battery. After all that it will still not charge. I have not completely sealed it up again but have sat the new digitizer tightly in place. It will not charge or turn on after being connected to a cable for several hours. What other components could need replacing?

Thank you for any help or insight!