Need to uninstall and reinstall Android on a Meizu M5

[AC Question]

Righto. It's come to my attention that the reason certain apps won't work on my Meizu is because there is malware built into Flyme. For example, Snapchat just won't log in. The apps with malware are the video and phone app, so I'm guessing I just need to wipe the phone completely and install vanilla Android. My question is how on earth do I go about doing this? I need the end result to be UNROOTED Android. Is there a plausible way of doing this? Thanks in advance!