Might be best to consider open source alternatives like Omnivore or Wallabag where there’s a facility to port data over. How big is your database? Some cross platform rtf files can have a tendency to bloat – is it possible to convert them to something else?
Not quite the same thing though – certain sites which provide personal favourite sections – (e.g watchlists on IA or Wikipedia, or bookmarks on programming sites – e.g. AHK or Stack Exchange) seek to foster such a reliance on their services for users. Something else that cheers each time reminded, the personal YouTube favourites list exceeds well over 1,000 already, and newsflash, Pichai/Zuck won’t be introducing categories any time soon. 😛