Weight 2 cohomology of graph complexes of cyclic operads and the handlebody group

We compute the weight 2 (resp.~top$-2$) cohomology of the Feynman transforms of the cyclic (co)operads $\mathsf{BV}$, $D\mathsf{BV}$, $\mathsf{Grav}$ and $\mathsf{HyCom}$. Using a result of Giansiracusa we compute in particular the weight top$-2$-cohomology of the handlebody group. We compare the result to the weight top$-2$ cohomology of the moduli space of curves $\mathcal M_{g,n}$, recently computed by Payne and the last-named author. We also provide another proof of a recent result of Hainaut--Petersen identifying the top-weight-cohomology of the handlebody group with the Kontsevich graph cohomology