I'm using the Xcadey crank in 172.5mm with titanium spindle since ~3 years and so far it is holding up fine.
the Xcadey Gen1 powermeter does not....
About me: ~80kG, 6~8000km per year, road only with loads of climbing in Japan, no races, sprints 1200W peak during Sunday group rides
From my subjective view, the 24mm version adds quite some weight to the Lexon carbon crank vs the DUB version, this is not the case for the Elilee, not sure if the titanium axle is having thinner walls or not. ==> it is not only the material but also about the detail spec (aka titanium grade), the shape as well as average wall thickness, besides others...
That being said, I have not yet seen a single broken titanium axle, not so sure about aluminum ones