Insert multiple images with caption in block in the beamer

Question

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Beamer Presentation
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\documentclass{beamer}

\mode<presentation> {
% The Beamer class comes with a number of default slide themes
% which change the colors and layouts of slides. Below this is a list
% of all the themes, uncomment each in turn to see what they look like.
\usetheme{AnnArbor}
\usecolortheme{beaver}

}
\usepackage{adjustbox}
\usepackage{graphicx} % Allows including images
\usepackage{booktabs} % Allows the use of \toprule, \midrule and \bottomrule in tables
\usepackage{hyperref}
\usepackage{caption}
\usepackage{ragged2e} 
\usepackage{multirow}
\usepackage[font=small]{caption}
\usepackage{wallpaper}
\usepackage{float}
\usepackage{multicol}
\usepackage[makeroom]{cancel}
\usepackage{tcolorbox}
\usepackage{datetime}
\usepackage[normalem]{ulem}
% Tikz
\usepackage{tikz}
\usetikzlibrary{shapes.geometric, arrows}
\tikzstyle{startstop} = [rectangle, rounded corners, minimum width=3cm, minimum height=1cm,text centered, draw=black, fill=red!30]
\tikzstyle{process} = [rectangle, minimum width=3cm, minimum height=1cm, text centered, draw=black, fill=orange!30]
\tikzstyle{decision} = [diamond, minimum width=3cm, minimum height=1cm, text centered, draw=black, fill=green!30]
\tikzstyle{arrow} = [thick,->,>=stealth]
\tikzstyle{coord} = [coordinate, on grid, node distance=6mm and 25mm, fill=white]

\usepackage{tikzscale}
\usetikzlibrary{quotes}
\usetikzlibrary{automata,calc,shapes,arrows,positioning,patterns}

\tikzset{decision/.style={diamond, draw, fill=blue!20, text width=4.5em, text
badly centered, inner sep=0pt}}
\tikzset{block/.style={rectangle, draw, fill=blue!20, text width=8em, text
centered, rounded corners,
 minimum width=3.5cm}}
\tikzset{line/.style={draw, -latex}}

\usepackage{smartdiagram}
\usepackage{pgfplots}
\pgfplotsset{compat=1.16}
\usepgfplotslibrary{fillbetween}
\usepackage{epsfig,graphicx,xcolor}
\usepackage{adjustbox}

\usetikzlibrary{external}
\tikzexternalize[prefix=tikz/,optimize command away=\includepdf,figure name=output]

% New Commands
\newcommand{\method}[1]{{\rm \textsf{#1}}}
\newcommand{\mini}{\mathop{\mbox{minimize}}}
\newcommand{\amin}{\mathop{\mbox{argmin}}}
\newcommand{\st}{\mbox{subject to}}
%\newcommand{\Ref}[1]{\mbox{\rm{(\ref{#1})}}}    % References with ()
\newcommand{\R}{\mathbb R}           % Real  numbers
\newcommand{\Z}{\mathbb Z}           % Integer  numbers
\newcommand{\B}{\mathbb B}           % Binary  numbers
\newcommand{\set}[1]{{\rm \mathcal{#1}}}
\newcommand{\pctext}[2]{\text{\parbox{#1}{\centering #2}}}
\newcommand{\eqdef}{\ensuremath{\overset{\mathclap{\text{\tiny def}}}{=}}}
\newcommand{\ita}[1]{\textit{#1}}
\newcommand{\pp}[1]{\textsf{{\color{blue}{PP note:} #1.}}\marginpar{\color{blue}{\textbf{PP}}}} 
\newcommand{\prob}[1]{{\rm \texttt{#1}}}
\newcommand{\code}[1]{{\rm \textsl{#1}}}
\newcommand{\mino}[1]{{\fontfamily{cmtt}\selectfont{#1}}}

\newtheorem{assumption}{Assumption}
\newtheorem{proposition}{Proposition}

\setbeamertemplate{theorems}[numbered]
\setbeamertemplate{title}[default][colsep=-4bp,rounded=true,shadow=false]
\setbeamertemplate{enumerate item}{(\alph{enumi})}
\setbeamertemplate{blocks}[rounded][shadow=false]
\setbeamertemplate{blocks}[framed]
\setbeamercolor{title}{fg = black, bg = red!30}
\setbeamercolor{structure}{fg = red!60}
\setbeamercolor{block title}{fg = black, bg =red!30}
\setbeamercolor{item projected}{fg = white, bg =red}

\newtcolorbox{myblock}[1]{
    colback=white,
    colbacktitle=red!30,
    coltitle=black,
    colframe=red!50,
    title=#1
}

%% TABLE
\usepackage{array}
\newcolumntype{L}[1]{>{\raggedright\arraybackslash}m{#1}}
\newcolumntype{C}[1]{>{\centering\arraybackslash}m{#1}}
\newcolumntype{R}[1]{>{\raggedleft\arraybackslash}m{#1}}

\usepackage[natbib=true,style=authoryear,backend=bibtex,useprefix=true]{biblatex}
\renewcommand*{\nameyeardelim}{\addcomma\addspace}
\addbibresource{bibs/ml.bib}

\DeclareCiteCommand{\cite}
  {\color{violet}\usebibmacro{prenote}}%
  {\usebibmacro{citeindex}%
   \usebibmacro{cite}}
  {\multicitedelim}
  {\usebibmacro{postnote}}

\DeclareCiteCommand{\parencite}[\mkcolorbibparens]
  {\usebibmacro{prenote}}%
  {\usebibmacro{citeindex}%
   \usebibmacro{cite}}
  {\multicitedelim}
  {\usebibmacro{postnote}}

\makeatletter
\newrobustcmd{\mkcolorbibparens}[1]{%
  \begingroup
  \footnotesize\color{violet}
  \blx@blxinit
  \blx@setsfcodes
  \bibopenparen#1\bibcloseparen
  \endgroup}
\makeatother


%
%----------------------------------------------------------------------------------------
%   TITLE PAGE
%----------------------------------------------------------------------------------------

\title[Research Presentation]{Research Presentation} % The short title appears at the bottom of every slide, the full title is only on the title page
\subtitle{A Review on Past Researches}



\author[Shresth Somya]{Shresth Somya}
\institute[IIT Delhi]{Indian Institute of Technology, Delhi
\\Department of Mechanical Engineering \\
\href{mailto:[email protected]}{[email protected]}
}
\titlegraphic{
    \includegraphics[scale = 0.20]{logo}
    \hspace{.5cm}
}
\date[\today]{\today}


\begin{document}

\begin{frame}{Possible Models}

\begin{columns}[T]

\column{0.3\textwidth-0.3\columnsep}

\begin{myblock}{Classification Models}
    \begin{minipage}[c][]{\linewidth}
    \begin{figure}
        \centering
        \includegraphics[width=0.8\textwidth]{example-image-a}
        \captionsetup{labelformat=empty}        
        \caption{\tiny ANN Model}  
    \end{figure}
    \vspace{-1.5}
    \begin{figure}
        \centering
        \includegraphics[width=0.8\textwidth]{example-image-b}
        \captionsetup{labelformat=empty}
        \caption{\tiny CNN Model}  
    \end{figure}
    \end{minipage}

\end{myblock}

\column{0.7\textwidth-0.7\columnsep}

\begin{myblock}{Sequential Models}
    \begin{columns}
        \column{0.3\textwidth-0.3\columnsep}
        \vspace{-2}
        \begin{figure}
        \centering
        \includegraphics[width=1.5\textwidth]{fexample-image-c}
        \captionsetup{labelformat=empty}
        \caption{\tiny Transformer Model}  
        \end{figure}
        \column{0.7\textwidth-0.7\columnsep}
        % \vspace{.1em}
        \begin{figure}
            \centering
        \includegraphics[width=0.65\textwidth]{example-image-d}
        \captionsetup{labelformat=empty}
        \caption{\tiny LSTM Model}
        % \vspace{.25em}
        \end{figure}
        \begin{figure}
        \centering
        \includegraphics[width=0.65\textwidth]{example-image-e}
        \captionsetup{labelformat=empty}
        \caption{\tiny RNN Model}  
        \end{figure}
    \end{columns}
    

\end{myblock}

\end{columns}
    
\end{frame}

\end{document} 

For the slide below, I have written the code above.

I want to make both blocks the same size and reduce the distance between the boundary and the image. I have mentioned the space in the image below.