For the power supply issue you, middle Atlantic makes rack mount power distribution.
Something like this Middle Atlantic PD-DC-300-12V 300W DC Power Distribution with 12V Outputs
I use these middle atlantic DC PDUs to power multiple converters. 24x12V outputs.
https://www.amazon.com/Middle-Atlantic-PD-DC-300-12V-Distribution-Outputs/dp/B07LFLNYGL