MacBook Pro 15 2017 Battery Condition: Replace Now
Your MacBook Pro needs to go in for service.

There are two telling signs that there is a (serious) hardware issue.  


The power button can't turn it on, but it will turn it off
You have 0A being measured at the battery


There could be an issue with the SMC chip itself (it's nothing more than a power controller chip) or the circuitry supporting the SMC (charging power is 12-16V while the SMC communicates and "controls" with 3V).  Without putting hands on the actual unit, it would be impossible to tell.

In other words, the SMC could be failing to charge the battery or the circuitry that charges the battery could have failed.

As far as the battery goes, it's entirely possible it's fine, it's just that it's not being measured properly (0A) given the symptoms.  However, it's not unheard of that a brand new battery with hardly any charge cycles goes bad and no longer holds a charge - it happens.

Again, without putting hands on, it would be next to impossible to tell and given the age (3 months), the best thing to do is send it in (mail in  if possible).  

It's a hardware issue and there's no getting around this. Firmware and a 3rd party boot loader will not address an issue concerning a chip that is technically supposed to be functional when the power is "off".

However, if you are so inclined to, open the back and disconnect the battery for 30 seconds.  That should reset the SMC.