\documentclass{article}
\usepackage{tabularray} 

\ExplSyntaxOn
\NewDocumentEnvironment{exptblr}{O{}m}
    {
    \use:x
    {
    \exp_not:N \begin{tblr}
    [\exp_not:n{#1}]
    {#2}
    }
    }
    {
    \end{tblr}
    }
\ExplSyntaxOff

\begin{document}

\end{document}