they’ve had a few SSL certificate renewal issues and the way they dealt with that was very dodgy (asking to just ignore it)
also manjaro beginners seem to often use the AUR which isn’t really supported for manjaro and break their install in the process
if this is your first time, then please buy a new SSD for Linux. You can replace the windows drive with the new drive, and have no worries of deleting data you might have forgotten. Your data is worth a lot more than the cost of an SSD.