nodes running on firestore functions

I have a working android app written in java. I need an experienced node.js consultant who can port a working functions code from the client android app to be implemented firestore functions and achieve the same functionality and output. Code currently takes 12 secs to run and update associated documents and collections (using transaction functionality to update them as a batch). Project will be successful if it run in less than 3-4sec after your node.js optimizations. functions should be exposed back to the android app using https express or similar.

Working Java code will be provided after awarding the project to protect our IP. Please do not bid if no similar project was done before. If you get in touch , you accept that the payment will be make when we are happy and the project is complete - (this is based on some consultants who demanded part payment in the past as part of milestones and never finished the projects ) .