Consider this MWE:

```
\documentclass{beamer}
\beamertemplatenavigationsymbolsempty
\setbeamersize{text margin left=10mm,text margin right=5mm} 
\setbeamertemplate{frametitle}[default][center]
\usepackage[many, listings]{tcolorbox}
\newcommand{\Com}[1]{\textcolor{comcolor}{#1}}
\usepackage{pgfplots}
\usepackage{nicematrix}
\definecolor{comcolor}{RGB}{10,161,119}
\definecolor{blue0}{RGB}{97,128,186}
\definecolor{blue2}{RGB}{209,215,230}
\definecolor{blue1}{RGB}{233,235,242,}
\begin{document}

\begin{frame}[t, fragile]
\frametitle{frame title}
\begin{columns}[t]
\begin{column}{0.5\textwidth}
\vskip -0.9cm
\begin{figure}
\begin{tikzpicture}
\begin{axis}[ybar,bar width=5mm,
	width=7cm,height=5cm,
	axis lines=middle,
	xmin=0.5,xmax=8.5,
	xtick={1,...,4,6,7,8},
	xticklabel style={anchor=south,text depth=0.5ex},
	extra x ticks={5},
	extra x tick style={xticklabel style={anchor=north}},	
	ytick=\empty,
	x axis line style={-},
	y axis line style={draw=none}]
 \addplot[fill=blue!50!white] coordinates {(2,-2) (5,3) (7,-1)};
\end{axis}
\end{tikzpicture}
\caption{a caption}
\end{figure}
\setbeamertemplate{itemize item}[circle]
\addtolength{\leftmargini}{-0.7cm}
\begin{itemize}[<+->]
\item line one
\item line two
\item line three
\end{itemize}
\end{column}

\begin{column}{0.5\textwidth}
%\vskip 0.5cm  <--- this changes of the first column too!
\begin{visibleenv}<2->
\begingroup\sffamily\renewcommand{\arraystretch}{1.5}\arrayrulecolor{white}%
\begin{NiceTabular}[c]{Wl{0.8cm}|Wl{1cm}|Wl{2.4cm}}%
[code-before = \rowcolor{blue0}{1} \rowcolors{2}{blue1}{blue2}]
\textcolor{white}{A} & \textcolor{white}{B} & \textcolor{white}{C}\\
\hline
&  & \\
\hline
 & & \\
\hline
 &  & \\
\hline
 &  & \\
\end{NiceTabular}\endgroup


\vskip 1.2cm
\begin{tcblisting}{boxsep=-2pt,top=0pt,bottom=0pt,left=5pt,right=5pt,colback=blue!5!white,
listing only,
listing options={escapechar=@, mathescape, name=countminoneline, basewidth = {.3em}}}
@\Com{process}@$(j, c)$
test code
test code
test code
\end{tcblisting}
\end{visibleenv}
\end{column}
\end{columns}
\end{frame}
\end{document}
```

I want to adjust everything in the right hand column so that it aligns better with the things in the left hand column. To do this I tried `\vskip 0.5cm` as you can see commented out line in the MWE. But this then shifts everything in the left hand column up! How can I adjust the right hand column without changing anything in the left hand column?