Can you describe the features you need?
Have you tried the existing extension called PWA, and would it satisfy your needs? https://discuss.flarum.org/d/23219-progressive-web-app-pwa-and-push-notifications
Note that as Flarum 2.x is still under development, it's unlikely that anyone will create a new extension or officially support the update of an existing extension to a beta version of Flarum. You will likely have to pay a developer to work with you on the unstable version, and again when the stable version gets finalized. This will likely require a lot more work than working with the current stable version of Flarum and update later when the free extensions get updated for the stable Flarum 2.0. It would also be unwise to put any of this into production until Flarum 2.x stable gets announced, a date which is currently not decided and could slow down the launch of your community.
