I’m not sure but it looks like it’s on Readwise’s end to implement an exporter that automatically syncs into another app (like they did for Roam): https://help.readwise.io/article/71-how-does-the-readwise-to-roam-export-integration-work
Until that happens you can play around with the a markdown export which you might be able to import, or even just directly paste into RemNote: https://help.readwise.io/article/121-how-can-i-customize-the-markdown-export
Customizations to the markdown format to even better fit RemNote (like done for Roam here: https://github.com/jammastergirish/Readwise2Roam) could be implemented by the communtiy. E.g. to turn some highlights into flashcards etc.