Use the unofficial API for Google Keep to export every notes and to be readable from Nextcloud Notes
Tested on :
- Python3.8
- Google Keep api : https://github.com/kiwiz/gkeepapi
- Nextcloud notes : https://apps.nextcloud.com/apps/notes
To login to your google account and to fetch google keep notes you need to create an application password https://support.google.com/accounts/answer/185833?hl=en