\begin{table}
\centering
\begin{tblr}[         %% tabularray outer open
]                     %% tabularray outer close
{                     %% tabularray inner open
colspec={Q[]Q[]Q[]Q[]},
hline{2}={1,4}{solid, black, 0.05em},
hline{3}={1-4}{solid, black, 0.05em},
hline{2}={3}{solid, black, 0.05em, l=-0.5},
hline{2}={2}{solid, black, 0.05em, r=-0.5},
hline{1}={1-4}{solid, black, 0.1em},
hline{6}={1-4}{solid, black, 0.1em},
cell{1}{1}={c=2}{halign=c},
cell{1}{2}={}{halign=c},
cell{1}{3}={c=2}{halign=c},
cell{1}{4}={}{halign=c},
}                     %% tabularray inner close
foo\_bar &  & banana\_fish &  \\
blah\_blah\_underscore & dollar\$sign & percent\%sign & ampersand\&sign \\
21.0 & 6 & 160 & 110 \\
21.0 & 6 & 160 & 110 \\
22.8 & 4 & 108 & 93 \\
\end{tblr}
\end{table} 
