Ehhh....that 'could' be possible with Fandaniel though unlikely as he could be masking his true motivations behind his theatrics. However, I don't find it likely and there's virtually 0 chance that Zenos cares enough about things to be secretly trying to save the world.

Fandaniel initially just came across as 'discount kefka' to me, and to be fair that may end up being all he is. But while I didn't like him at first his last couple of scenes have been winning me over as an entertaining, if not deep, antagonist.

Zenos meanwhile I would have liked more if he'd stayed dead. His quest to reclaim his body could have been a great storyline, but it was rushed through and we never see him have to try or struggle. Aside from finding his 'all I want is to fight someone strong' motivation unappealing, part of my issue with him is he never seems to struggle. He never really has to 'try.' He basically seems to just brute force his way to getting his body back rather than needing to be clever or think outside the box, even able to overpower Varis and force Elidibus to flee despite being in a weaker body at the time. And while we have been giving setbacks to Zenos and Fandaniel's plans in 5.5, it feels more like Fandaniel specifically as Zenos' part hasn't really come into play.

It feels like everything effortlessly goes Zenos' way except for when the script says 'okay now it's time for him to lose' at the end of 4.0. This could be used to make him feel more threatening, but at the same time the game is adverse to giving his victories weighty consequences. Y'sthola getting hurt is just a means to give spotlight to other characters for a bit, Gaius and Estinien get away just fine. Yugiri isn't killed when her assassination attempt fails. For me it kind of puts Zenos in an awkward middle ground where he's overpowered but the consequences of him being overpowered are nullified by npc plot armor, preventing him from being a truly terrifying force within the story. He can trounce just about everyone, including the WOL pre ala mhigo, but isn't allowed to really hit us where it hurts. So he feels....both overpowered and defanged at the same time. He undoes Garlemald from within but that's not affecting characters we know and care about. He kills Varis but the ending of the negotiations kind of torpedoed Varis as a character already.