Text height with multirow in a tabularx table

Question

I'm facing trouble with multirow, when I used multirow in the last column of the table, the text becomes very close to the top margin and the text is not justified, while in other columns and rows text height is okay. I also used makecell[t] and pbox both of them help to justify text however text height remains an issue also they both worked without multirow, so I wanted to use multirow and normal text height not close to the top margin, can you please help here. I'm sharing code and an image.

\documentclass[fleqn]{IEEEtran}
\begin{table*}[t]
\caption{ }
\renewcommand{\arraystretch}{1.5}
\setlength{\tabcolsep}{4.5pt}
\label{Table:1} %cXXX  {\linewidth} 
\begin{tabularx} {\textwidth} {|c|p{3cm}| p{5cm}|p{7.5cm}|}
\hline
 \multicolumn{1}{|c}{AAAAAA(s)}& \multicolumn{1}{c}{AAAAAAA(s)} %& \multicolumn{1}{c}{ Source(s)}
& \multicolumn{1}{c}{AAAAAAAA (s)} & \multicolumn{1}{c|}{AAAAA(s)}
          
\\
\hline
\& &\multirow{4}{7.5cm}{{}} \\ \cline{1-3} %\cline{4-5}



& & &  \\ \cline{1-3}


 & & &    \\\cline{1-3}
\& &  &   \\\cline{1-3}

\textit{Our work}&   & &   \\\hline
\end{tabularx}
\end{table*}
\end{document}

Answer 1

Your MWE is not complete and contain errors, so I can only guess, what you like to have. Anyway, if you use tabularx table, at list one column should be of X type. For example, the last one:

\documentclass[fleqn]{IEEEtran}
\usepackage{multirow, tabularx}

%---------------- Show page layout. Don't use in a real document!
\usepackage{showframe}
\renewcommand\ShowFrameLinethickness{0.15pt}
\renewcommand*\ShowFrameColor{\color{red}}
%---------------------------------------------------------------%
\usepackage{lipsum}% For dummy text. Don't use in a real document

\begin{document}
\begin{table*}[t]
\caption{ }
\renewcommand{\arraystretch}{1.5}
\setlength{\tabcolsep}{4.5pt}
\label{Table:1} %cXXX  {\linewidth}
\begin{tabularx}{\textwidth} {|c|p{3cm}| p{5cm}|X|}
    \hline
AAAAAA(s)   & AAAAAAA(s)    & AAAAAAAA (s)  & AAAAA(s)  \\
    \hline
            &               &               & \multirow{4}{=}{\lipsum[66]}                   
                                                        \\ \cline{1-3}
            &               &               &           \\ \cline{1-3}
            &               &               &           \\ \cline{1-3}
            &               &               &           \\ \cline{1-3}
\textit{Our work}
            &               &               &           \\
    \hline
\end{tabularx}
\end{table*}
\end{document}

Edit: Using it, your table will not protrude out of text borders, as you can see on mage below. It is also not clear, why you for column headers use multicolumn cells. They only overwrite column settings and make a mess with vertical lines.

Addendum: For exercise and fun you may investigate features of the tabularray packages. Using it, the code of above table can be:

\documentclass[fleqn]{IEEEtran}
\usepackage{tabularray}

%---------------- Show page layout. Don't use in a real document!
\usepackage{showframe}
\renewcommand\ShowFrameLinethickness{0.15pt}
\renewcommand*\ShowFrameColor{\color{red}}
%---------------------------------------------------------------%
\usepackage{lipsum}% For dummy text. Don't use in a real document

\begin{document}
    \begin{table*}[t]
    \caption{ }
    \label{Table:1}
\begin{tblr}{hlines, vlines,            % lines in table
             colspec= {c Q[j,wd=3cm] Q[j,wd=5cm] X[j]},
             rowsep=3pt,                % vertical space between rows borders
                                        % and (heigher) contents in it
             row{1} = {font=\bfseries}, % text in the first row is boldface
             vspan = even               % height of rows spanned by multi row cell
                                        % is evenly distributed
             }  % table preamble, defaine its layout
AAAAAA(s)   & AAAAAAA(s)    & AAAAAAAA (s)  & AAAAA(s)  \\
            &               &               & \SetCell[r=5]{j} \lipsum[1] % define multi row cell
                                                        \\
            &               &               &           \\
            &               &               &           \\
            &               &               &           \\
\textit{Our work}
            & short text    & \lipsum[1][1] &           \\
\end{tblr}
\end{table*}
\end{document}

For more information please read package's dpcumentation.