The TxGraffiti zero forcing versus independence conjecture for subcubic graphs

Let $G$ be a connected graph, let $\Delta(G)$ denote its maximum degree, let $\operatorname{Z}(G)$ denote its zero forcing number, and let $\alpha(G)$ denote its independence number.

TxGraffiti's conjecture. If $G \not\cong K_4$ and $\Delta(G)\leq 3$, then

$$\operatorname{Z}(G)\leq \alpha(G)+1.$$

The conjecture was proposed for connected graphs of maximum degree at most $3$. It is refuted by both a connected subcubic graph and a connected cubic graph: the former has $\alpha(G)=9$ and $\operatorname{Z}(G)=11$, while the latter has $\alpha(G)=15$ and $\operatorname{Z}(G)=17$, so the claimed bound fails in each case.