Sadly, the newer 2016 onward MacBook Pro’s don’t truly turn off when you think they are. They just go into a sleep mode. So if your system was not fully charged its likely to have fully drained the battery to the point its can’t recover being unplugged for so long.
You’ll need a means to see whats happening within the USB-C connection to your power adapter like this one [https://satechi.net/products/satechi-type-c-power-meter-for-new-macbook-macbook-pro-type-c-devices|Satechi USB-C Power Meter]. That way to you tell of the power adapter and its cable are working correctly or if you’ll need to replace the battery.
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Reference [https://support.apple.com/en-us/HT204267|If your Mac doesn't turn on or start up]
Sadly, the newer 2016 onward MacBook Pro’s don’t truly turn off when you think they are. They just go into a sleep mode. So if your system was not fully charged its likely to have fully drained the battery to the point its can’t recover being unplugged for so long.
You’ll need a means to see whats happening within the USB-C connection to your power adapter like this one [https://satechi.net/products/satechi-type-c-power-meter-for-new-macbook-macbook-pro-type-c-devices|Satechi USB-C Power Meter]. That way to you tell of the power adapter and its cable are working correctly or if you’ll need to replace the battery.