Conceal with the highlighting of matching begin/end latex environment

Question

I want to use vim conceal feature with the highlighting of matching begin/end latex environment (vimtex plugin). When I use the following code

syn match texStatement '\\begin{itemize}' contained conceal cchar=-
syn match texStatement '\\end{itemize}' contained conceal cchar=-

with set conceallevel=2, I get the \begin{itemize} and \end{itemize} concealed into -. But when I hover on \begin{itemize} the matching \end{itemize} (concealed in -) does not get highlighted.

So I added the transparent argument

syn match texStatement `\\begin{itemize}` transparent contained conceal cchar=-
syn match texStatement `\\end{itemize}` transparent contained conceal cchar=-

Now I get the highlighting of matching parentheses but the \\begin{itemize} and \\end{itemize} are not completely concealed, instead they get concealed into {itemize}. I don't know how to use the contained and contains arguments to get around this.