table with siunitx - alignment on precision mode

In a test on making tables, i use the cool package siunitx for having some defined precision on values after the comma and to aligning these values on the dot in the middle column but unfortunately, it is doing some alignment on the text Val 2, the $beta$ remained untouched. Does the number 2 being considered as a value for siunitx, even with the text before as it was like a 2.00 ?
or do i have to create a separate table for the first line (Val 1 … Val 3) – not convinced…

here is my code :

documentclass[11pt,a4paper]{article}
usepackage[utf8]{inputenc}
usepackage[T1]{fontenc}
usepackage{frcursive}
usepackage{amsmath}


% le package qui pemet de définir des unités et leur affichage
usepackage{siunitx} % Required : alignement des valeurs etc.
sisetup{
    round-mode          = places, % Rounds numbers
    round-precision     = 2, % to 2 places
}

begin{document}

%exemples de tableau
noindentbegin{cursive}Des tableaux:end{cursive}
begin{table}[h!]
    begin{center}

    label{tab:table1}
        
        begin{tabular}{l|c|r} % Alignements: left, center, right
            textbf{Val 1} & textbf{Val 2} & textbf{Val 3}\
            $alpha$ & $beta$ & $gamma$ \
            hline
            1 & 1110.1 & a\
            2 & 10.1 & b\
            3 & 23.113231 & c\
        end{tabular}
    caption{Valeurs basiques}

vspace{1cm}    

    label{tab:table2}
    
    begin{tabular}{l|S|r} % c devient S ==> unitsx
        textbf{Val 1} & textbf{Val 2} & textbf{Val 3}\
        $alpha$ & $beta$ & $gamma$ \
        hline
        1 & 1110.1 & a\
        2 & 10.1 & b\
        3 & 23.113231 & c\
    end{tabular}
  caption{Valeurs alignées et arrondies}
  
    end{center}
  end{table}


end{document}

documentclass[11pt,a4paper]{article}
usepackage[T1]{fontenc}
usepackage{frcursive}
usepackage{amsmath}
% le package qui pemet de définir des unités et leur affichage
usepackage{siunitx} % Required : alignement des valeurs etc.
sisetup{   % this is now globally set, you ma consider to move it inside table
    round-mode      = places, % Rounds numbers
    round-precision = 2, % to 2 places
}

begin{document}
%exemples de tableau
noindentbegin{cursive}Des tableaux:end{cursive}
    begin{table}[h!]
centering
    begin{tabular}{l|c|r} % Alignements: left, center, right
textbf{Val 1} & textbf{Val 2} & textbf{Val 3}\
$alpha$ & $beta$ & $gamma$ \
    hline
1 & 1110.1      & a\
2 & 10.1        & b\
3 & 23.113231   & c\
    hline
    end{tabular}
caption{Valeurs basiques}
label{tab:table1}
   
vspace{2baselineskip}
    begin{tabular}{l|S[table-format=4.2]|r}             % <---
textbf{Val 1}  & {textbf{Val 2}} & textbf{Val 3}  \  % <---
$alpha$}       & {$beta$}        & $gamma$        \  % <---
    hline
1 & 1110.1      & a\
2 & 10.1        & b\
3 & 23.113231   & c\
    hline
    end{tabular}
caption{Valeurs alignées et arrondies}
label{tab:table2}
  end{table}
end{document}