The error codes are the following:
* ***PFM001 -*** There may be an issue with the System Management Controller (SMC)
* ***PPT001 -*** The battery was not detected.
These make sense at you took the battery out.
As you are getting past POST I suspect you have a bad drive or the OS is corrupted.
Using a second make I would create a bootable thumb drive with the correct macOS this system needs. Booting up with a BootCamp setup drive adds another layer of confusion.
It’s also possible the discrete GPU is failing. Are you able to boot up in Target Disk Mode (pressing the ***T*** startup key) if you get the Thunderbolt Icon on the screen that tells the GPU has a problem.