Vertical alignment in cell table Latex

Question

I created this table in Latex: As you can see the text (MNIST, CIFAR10,...) in the column Dataset is not vertical aligned. How can I put that strings in the middle of the cell? This is my code:

\begin{table}[!hbt]
\caption{Multi-row table}
\begin{center}
\begin{tabular}{|c|c|c|c|c|}
    \hline
    Category & Epochs per round & Dataset & FedAvg & FedCurv \\
    \hline
    \multirow{9}{2.5cm}{\centering Uniform Distribution} &  1 & MNIST & accuracy & accuracy \\ 
    & 10 &  & accuracy & accuracy \\ 
    & 30 &  & accuracy & accuracy \\ \cline{2-5}
    & 1 & CIFAR10  & accuracy & accuracy\\
    & 10 &  & accuracy & accuracy\\ 
    & 30 &  & accuracy & accuracy \\\cline{2-5}
    & 1 & TinyImageNet & accuracy & accuracy \\
    & 10 &  & accuracy & accuracy \\
    & 30 &  & accuracy & accuracy \\
    \hline
    \multirow{9}{2.5cm}{\centering Quantity Skew} &  1 & MNIST & accuracy & accuracy \\ 
    & 10 &  & accuracy & accuracy \\ 
    & 30 &  & accuracy & accuracy \\ \cline{2-5}
    & 1 & CIFAR10 & accuracy & accuracy\\
    & 10 & & accuracy & accuracy\\ 
    & 30 &  & accuracy & accuracy \\ \cline{2-5}
    & 1 & TinyImageNet & accuracy & accuracy \\
    & 10 & & accuracy & accuracy\\
    & 30 &  & accuracy & accuracy \\
    \hline
    \multirow{9}{2.5cm}{\centering Quantity Labels Skew} &  1 & MNIST & accuracy & accuracy \\ 
    
...

    \multirow{9}{2.5cm}{\centering Covariate Shift} & 1 & MNIST & accuracy & accuracy \\ 
    & 10 & & accuracy & accuracy \\ 
    & 30 &  & accuracy & accuracy \\ \cline{2-5}
    & 1 & CIFAR10 & accuracy & accuracy\\
    & 10 &   & accuracy & accuracy\\ 
    & 30 &  & accuracy & accuracy \\ \cline{2-5}
    & 1 & TinyImageNet  & accuracy & accuracy \\
    & 10 &  & accuracy & accuracy\\
    & 30 &  & accuracy & accuracy \\
    \hline
\end{tabular}
\end{center}
\label{tab:multicol}
\end{table}

Answer 1

I suggest to use the tabularray package instead of a traditional tabular.

Unrelated to the problem, but don't use the center environment inside a float, this will add additional vertical spacing. You can use \centering instead.

\documentclass{article}

\usepackage{tabularray}

\begin{document}


\begin{table}[!hbt]
\caption{Multi-row table}
%\begin{center}
\centering
\begin{tblr}{|c|c|c|c|c|}
    \hline
    Category & Epochs per round & Dataset & FedAvg & FedCurv \\
    \hline
    \SetCell[r=9]{} Uniform Distribution &  1 & \SetCell[r=3]{} MNIST & accuracy & accuracy \\ 
    & 10 &  & accuracy & accuracy \\ 
    & 30 &  & accuracy & accuracy \\ \cline{2-5}
    & 1 & \SetCell[r=3]{}CIFAR10  & accuracy & accuracy\\
    & 10 &  & accuracy & accuracy\\ 
    & 30 &  & accuracy & accuracy \\\cline{2-5}
    & 1 & \SetCell[r=3]{}TinyImageNet & accuracy & accuracy \\
    & 10 &  & accuracy & accuracy \\
    & 30 &  & accuracy & accuracy \\
    \hline
\end{tblr}
%\end{center}
\label{tab:multicol}
\end{table}

\end{document}