You can export your content from Confluence into Boost Note one doc or all at once, here's how:
Exporting individual Confluence docs into Boost Note
In Confluence, select the doc you want to export and click '...' button in the top right
Export file as Word
Upload files in the Boost Note
Exporting Confluence docs in bulk into Boost Note
In Confluence, go to Space Settings for the space you're looking to export and select the Content tools section
Click the Export tab, select HTML and Export
Export file as HTML
Upload files in the Boost Note