Stability comparison of europium(II) and ytterbium(II) ions

“Which one of the lanthanoids given below are most stable in divalent form?” This question was asked in JEE Main 2022 (Indian entrance test for engineering). Now the question had both $\ce{Eu^2+}$ and $\ce{Yb^2+}$ as the options.


My thought was that since $\ce{Yb^2+}$ has $f^{14}$ configuration it should be somewhat more stable than the half filled $\ce{Eu^2+}$. The answer key however says that $\ce{Eu^2+}$ is more stable. It would be helpful if someone could explain why that could be true. Relevant data of Reduction potentials would be helpful as well ( I tried to find it but without much success).


