Help troubleshooting MacBook Pro 14" 2021 (A2442): won't boot, battery

I have a used MacBook Pro 14" (model A2442, 2021) and it won't turn on. I've done some troubleshooting and would appreciate any advice on next steps.

What I've tried:

  • Charged for 3 hours via USB-C
  • Tried external monitor (no output)
  • SMC reset attempt (hold power 10 seconds)
  • All key combinations for recovery mode

Diagnostics so far:

  • When plugged into USB-C power bank, one port draws 3-12W (varying/cycling), the other ports only 0.1-0.3W
  • No response to any key presses
  • No startup chime, no display output on internal or external monitor
  • Power draw pattern happens automatically when plugged in (seems like boot loop?)

Opened it up (followed iFixit guide):

  • No visible water damage or corrosion
  • Battery connector logic board side: 1.5V
  • Battery side: 0.0V (completely dead battery?)
  • Tried booting with battery disconnected - same behavior

Questions:

  1. Could the dead battery be preventing boot even with external power?
  2. Is this likely a logic board issue?
  3. Why is the battery showing exactly 0V? Isnt that weird?
  4. Worth trying anything else before taking it for professional repair?

The machine looks pristine physically, so I'm hoping it's fixable. Any insights appreciated.

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You need a USB-C power meter to monitor the voltage to see if the charging logic is failing. You should see about 5 volts and then it should jump to about 18 if it does the charging logic is working and the battery is being charged. If not there is a deeper logic board issue which will require deeper diagnostics at the board level.

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