Help me choose a controller for ECU

Im building an ecu unit for my classic car, no I'm not using mega squirt snd that because I'm not controlling the injection or ignition. I was going to use an atmega chip due to my experience using them but I wpuld like to drive a reasonable size colour display and have up to two cameras recording whic is clearly above what the arduino can.handle. The only other option seems to be a raspberry pi which seems like over kill being that itd only be used to drive the screen and two cameras. Currently Ihave resigned to use the pi and a atmega328 together so I can still do the real time tasks I need.

What a I am asking is, is there a better way? I am proficient in c++ and assembly but not enough to write a driver for a chip I've never used