When running lambda, chrome needs to recompiled with the same os distribution lambda uses.
This makes it problematic to run the jsreport.Local. It could maybe work, but it sounds to me like a bad idea even to try it.
I would probably instead run jsreport as extra lambda function. We have a tutorial for it here
https://jsreport.net/learn/aws-lambda-serverless
And then invoke the extra reporting lambda function from your c# lambda function.
Have you considered this approach?