MacBook Pro 2019 suddenly dead and does not turn on
When you have power issues, the most likely cause is hardware.

Follow precisely the steps to reset your SMC
https://support.apple.com/en-us/HT201295

This is something you want to do once, not regularly reset it - more than three resets in a month = a trip to repair for us at work.
Your machine has a T2 chip, so that also controls power on, so in rare cases if you can't boot to external media / Internet Recovery, you might have success reviving or restoring the firmware portion of the T2 system which can make all the data unrecoverable - so also read that through a couple times before attempting any portion in the middle.

https://support.apple.com/guide/apple-configurator-2/revive-or-restore-mac-firmware-apdebea5be51/mac

When these steps fail or you decide it’s hardware, seek someone trained to diagnose and repair your mac. Good options are at the consultant and Apple service locations listed at https://locate.apple.com