The Packaging mostly takes up to 30 minutes on my PC, and a lot less on my laptop.
Jeez, that sounds like your system is running out of memory and swapping solidly for 25 minutes or something. IIRC the packaging step consists solely of creating package.nw, which is basically adding all your project files to a zip. So it shouldn't take significantly longer than doing the same from Windows. I'd imagine it's limited by your hard disk write speed. It also doesn't compress any NW.js files so the NW.js version should have no impact on this at all.
You could try disabling antivirus/Windows Defender in case that is slowing it down (AV may scan everything written to disk in real-time).
30 minutes is extreme and sounds like some kind of fault condition (or poor hardware? :-\) but assuming export can finish in <5 minutes, that seems reasonable to me - I never thought anyone would export regularly, you do all your testing from C2's preview mode then you export once for publishing, right?