I want to center the arrows as well as the \vdots, but can't figure out how. I want to create a figure, but thought the smartest way to do it is to create it as an table. Any help would be appreciated! (As a bonus question: How do I center "Cal-23"?).
\documentclass[12pt]{book}
\usepackage[]{graphicx}
\usepackage[]{color}
\usepackage{alltt}
\usepackage[a4paper, width = 160mm, top = 35mm, bottom = 30mm,
bindingoffset = 0mm]{geometry}
\usepackage[utf8]{inputenc}
\usepackage{ragged2e}
\usepackage{xcolor}
\usepackage{amsmath}
\usepackage{fancyhdr}
\usepackage{tabularray}
\usepackage{tabularx}
\begin{document}
\begin{table}
\centering
\begin{tblr}{
cell{1}{6} = {c=2}{},
vline{1,13} = {1}{},
vline{1,4,7,10,13} = {3}{},
vline{1-4,7,10,13} = {5}{},
vline{4-7,10,13} = {7}{},
hline{1-8} = {-}{},
hspan = even,
}
& & & & & Cal-23 & & & & & & \\
& $\downarrow$ & & & $\downarrow$ & & & $\downarrow$ & & & $\downarrow$ & \\
& Q1/23 & & & Q2/23 & & & Q3/23 & & & Q4/23 & \\
$\downarrow$ & $\downarrow$ & $\downarrow$ & & $\downarrow$ & & & $\downarrow$ & & & $\downarrow$ & \\
Jan/23 & Feb/23 & Mar/23 & & Q2/23 & & & Q3/23 & & & Q4/23 & \\
& & & $\downarrow$ & $\downarrow$ & $\downarrow$ & & $\downarrow$ & & & $\downarrow$ & \\
& & & Apr/23 & May/23 & Jun/23 & & Q3/23 & & & Q4/23 & \\
& & & & & & $\vdots$ & $\vdots$ & $\vdots$ & & $\vdots$ &
\end{tblr}
\end{table}
\end{document}