Local antimagic chromatic number of even-by-odd flower-bouquet graphs

Let $r$ and $s$ be integers, with $r$ even and $r\ge 2$, and $s$ odd and $s\ge 3$. Let $rFB(s)$ denote the corresponding flower-bouquet graph, and let $\chi_{la}(G)$ be the local antimagic chromatic number of a graph $G$. The even-by-odd flower-bouquet conjecture.

$$\chi_{la}(rFB(s))=3.$$

The paper proves the analogous equality for odd $r,s\ge 3$, while the even-$r$, odd-$s$ case is posed as an open problem.