I think he wins with a similar map to Trump 2016, plus maybe MN and VA. I don't think he'd actually win NJ, but it may have even been within 5 points.
Thinking more about it, Chris Christie is the modern Nixon. Someone who could have been remembered so fondly, but destroyed his reputation with a completely unnecessary scandal.
But unfortunately, these things are part of people's personalities. Even if Bridgegate never happened and Christie made it to the White House, it's very possible that he would have been felled by something else.
He would lose NJ by 6%, 51%-45%. In 2020, it would be 53%-44% against Biden.
I agree with everything else you have said, I think in 2020 Christie would hold onto AZ by 4%, and cling onto Georgia by 0.8 or 1%. Christie would take COVID-19 seriously which helps him with voters nationwide, and helps him keep the election close with Biden but I'm not sure who would actually win.