Hi there,
Hope you are doing good, first introduce myself i am experienced android developer, developed many application as well as published in play store itself.
I saw your requirement website to mobile app, i am very well experienced, developed many application like this. Webservice(api) also we will write. Will follow latest technologies android studio, kotlin, MVVM design pattern support till latest version.
I am eagerly to do this project within your budget, please feel free to contact for further discuss and i will share my previous work as well, hoping positive respond.