Hi. I understand that you want an item management/inventory application. I have seen the sample app, and I can make a similar one for you. I will be using Flutter for making the app. In the past, I have worked on a large scale services app which fills the gap between tailor and customer. If you want I can share a video of that app as well. I can work with both REST API or Firebase as the back-end.
I would love to work on your project, and will put my best efforts to it. Please share more details in chat and we can start working on it.
Thanks,
Tanzil