Not powering on after rear case and battery replacement

After doing a iphone 5 repair I found that the power would not come on. reconnected the old battery and tested for power. There was no power after the swap. disconnected everything back to the power button and checked for cable damage, issues with connections and even the placement of the power button. there was no issues found and only concern was one of the signal ribbons at the top of the phone was seperated from the ribbon. other issue is the lightning connector is missing one washer. could a missing washer and a ripped cellular antenna cause a concern

or is there something else im missing.

*note the phone was in a severely bent aluminum frame as well as had battery issues with longevity, the front glass is severely cracked and scheduled for replacement later on rather than now. Also during inital teardown found one screw missing but iphone was working properly*

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