As for your question about the sample library: NP5 supports the newest Nord sample format version 4 (.nsmp4) but the sample library which allows you to download .nsmp4 samples and use them on the NP5 is not yet available from Nord's webpage. Nord Sound Manager v7.60 and beyond support converting samples from their original .nsmp format into .nsmp4 format when these are loaded on the NP5, so you can at least download .nsmp samples from their Sample Library v2 and also from this forum.
Here's the information about this from the Nord Sound Manager update history:
v7.60 (2021-08-13)
- Mac OS app is now notarized by Apple
- Fixed bug where conversion to .nsmp3 format did not work as expected for Nord Wave 2
- Fixed bug where conversion of multiple .nsmp files could cause application to shut down
- User created .nsmp files can now be converted to .nsmp4 format for use on Nord Piano 5
- Added support for Mac OS dark mode