It's definitely starting to look like both meta adaptation and synergy problems. While the org is no stranger to bad starts, it looks like this issue goes beyond that.
The roster is too steady; plain and simple. Along with that they're still green on some edges with Nemesis' rookie status and Bwipo's full starting spot. Think TSM or SKT last year where their identities were so clear they were beat because there were no fearless carries game after game. The best Fnatic has is Hyli and he's got a track record of being downloaded.
Being aggressive vs being meticulous. That's the biggest change they're struggling with in their lost members.