About the Alternatives，
We are working on a new software based on the latest features of IOS14, with Pencilkit natural gesture scribbling, improved note data structure, system files integration and sidebar, we are calling it marginsketch.
We are also trying to improve some of the problems with MarginNote by refactoring MarginNote 4, the old framework and data structure makes some changes difficult to make, we will try our best to fix the existing shortcomings of MarginNote 3 as much as the framework allows, including sync, file management, tagging and filtering, etc.Really sorry about that!