Seeing as how no one else has chimed in, I’ll take a stab at it.
As far as I know, a minimum configuration of battery screen and dock (to permit connect-to-boot) allows all devices to boot properly (you could exclude the dock and jump start it with tweezers). I haven’t tested this on a 11 Pro Max but I don’t see any reason why it shouldn’t.
The question here might be if the logic board was damaged, either when disassembled (I doubt it, you are an experienced tech) or the circuitry was damaged before hand, hence why you were asked to replace the coil. Give us a bit of background on the device prior to repair.
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