Vertical alignment in cell table Latex - 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}