Change position of Chapter number and word "chapter" on chapter title page

Question

I am writing my thesis in Latex and would like to create a nice chapter title page. I would like to place the chapter number and the word chapter on the right side, slightly overlapping the image I inserted at the bottom. Further, I would like to increase the size of the chapter number and the word chapter. I would like the chapter title to stay where it is. Additionally, I would like the dummy text to be positioned below the chapter title. I have tried a lot, but cannot seem to figure out how this works.

I have attached a picture of what I am aiming for.

Please see my MWE below. I would be grateful for any help!

MWE:

\documentclass[a4paper, twoside, 12pt, final]{report}
\usepackage[utf8]{inputenc}

% custom section headers
\RequirePackage{titlesec}
\usepackage{tikz}
\usepackage{lipsum}

% I added this
\RequirePackage{color}
\definecolor{RoyalRed}{RGB}{157,16, 45}
\titleformat{\chapter}[display]
{ \normalsize \LARGE  \color{black}}  {\tikz[remember picture,overlay] \node[opacity=0.9,inner sep=0pt,anchor=south] at (current page.south){\includegraphics[width=\paperwidth,height=10cm]{blue.jpg}};
    \flushright \large \color{RoyalRed} \MakeUppercase { \chaptertitlename}%
        \rlap{ \resizebox{!}{1.5cm}{\thechapter}}
  }
  {10pt}{\bfseries\huge}
\titlespacing*{\chapter}{0pt}{-70pt}{180pt} 

\begin{document}


\chapter{Introduction}
\lipsum[2]

\end{document}

Answer 1

Try this code. (I understood that the figure goes at the top of the page.)

Change the font size of the word chapter and of the chapter number using \fontsize{<size>}{<skip>}. Modify their position using xshift and yshift

Also \titlespacing*{\chapter}{<space left>}{<space above>}{<space below>} for the chapter title.

\documentclass[a4paper, twoside, 12pt, final]{report}
\usepackage[utf8]{inputenc}

% custom section headers
\RequirePackage{titlesec}
\usepackage{tikz}
\usetikzlibrary{positioning} % added <<<<<<<<<<<<<
\usepackage{anyfontsize} % added to change fonts with pdflatex <<<<<<<<<<<<<

\usepackage{lipsum}

\RequirePackage{xcolor}
\definecolor{RoyalRed}{RGB}{157,16, 45}

\newcommand{\ChapLabel}{\fontsize{36pt}{44pt}\selectfont \color{RoyalRed} \MakeUppercase{\chaptertitlename}}% set the word Chapter
\newcommand{\ChapNum}{\fontsize{120pt}{144pt}\selectfont \color{RoyalRed} \thechapter}% set the chapter number
\newcommand{\MakeChap}{\ChapLabel\enspace\ChapNum}

\titleformat{\chapter}[display]
{ \normalsize \LARGE  \color{black}}  {%
    \begin{tikzpicture}[remember picture,overlay] 
    \node(blue)[opacity=0.9,inner sep=0pt,anchor=north] at (current page.north){\includegraphics[width=\paperwidth,height=10cm]{blue.jpg}};
    \node [below= of blue.south east, anchor=base east, xshift=-\marginparsep, yshift=-1ex] {\MakeChap};
\end{tikzpicture}}
{10pt}{\bfseries\huge}
\titlespacing*{\chapter}{0pt}{170pt}{20pt} % changed <<<<<<<<<<<<<<

\begin{document}    
    \chapter{Introduction}
    \lipsum[2-8]    
\end{document}

UPDATE after follow up question. (Figure at the bottom and subtitles.)

Use \Schapter{<chapter title>}{<subtitle>} to add a subtitle.

% !TeX TS-program = pdflatex

\documentclass[a4paper, twoside, 12pt, final]{report}
\usepackage[utf8]{inputenc} 
% custom section headers
\RequirePackage{titlesec}
\usepackage{tikz}
\usetikzlibrary{positioning} % added <<<<<<<<<<<<<

\usepackage{anyfontsize} % added for change fonts with pdflatex <<<<<<<<<<<<<   
\usepackage{fancyhdr} % added <<<<<<<<<<<<<
\fancypagestyle{plain}{% style plain >>> empty for chapter page
    \fancyhf{}
    \renewcommand{\headrulewidth}{0pt}
    \renewcommand{\footrulewidth}{0pt}
}

\usepackage{lipsum} 
\RequirePackage{xcolor}
\definecolor{RoyalRed}{RGB}{157,16, 45}

\newcommand{\ChapLabel}{\fontsize{30pt}{36pt}\selectfont \color{RoyalRed}\sffamily \MakeUppercase{\chaptertitlename}}% set the word Chapter
\newcommand{\ChapNum}{\fontsize{120pt}{144pt}\selectfont \color{RoyalRed}\sffamily \thechapter}% set the chapter number
\newcommand{\MakeChap}{\vspace*{10cm}\ChapLabel\enspace\ChapNum}

\titleformat{\chapter}[display]
{ \normalsize \LARGE  \color{black}}  {%
    \enlargethispage{-7cm}
    \begin{figure}[b]%      
            \begin{tikzpicture}[remember picture,overlay] 
                \node(blue)[opacity=0.9,inner sep=0pt,anchor=south] at (current page.south){\includegraphics[width=\paperwidth,height=10cm]{blue.jpg}};
                \node (chap) [above= of blue.north east, anchor=south east, xshift=-\marginparsep-\marginparwidth-30pt, yshift=-4ex] {\ChapLabel};
                \node [right= of chap.south east, anchor=base west, xshift= -\marginparwidth+12ex, yshift=-6ex] {\ChapNum};
            \end{tikzpicture}
    \end{figure}}       
{10pt}{\bfseries\huge}
\titlespacing*{\chapter}{0pt}{-30pt}{20pt} % changed <<<<<<<<<<<<<< 

\newcommand{\Schapter}[2]{\chapter[#1]{#1\\[1ex] \parbox{0.7\linewidth}{\large#2}}}% add subtitles <<<<<<<<<<<<<<<

\begin{document}    
    \Schapter{Introduction}{Nam lacus libero, pretium at, lobortis vitae, ultricies et, tellus}
    \lipsum[2-8]    
\end{document}

Answer 2

From what I understand, this is what you want:

\documentclass[a4paper, twoside, 12pt, final]{report}
\usepackage{tikz}
\usepackage{lipsum}
\usepackage{xcolor}
\definecolor{RoyalRed}{RGB}{157,16, 45}

\makeatletter
\def\@chapter[#1]#2{
\ifnum \c@secnumdepth >\m@ne
\refstepcounter{chapter}%
\typeout{\@chapapp\space\thechapter.}%
\addcontentsline{toc}{chapter}%
{\protect\numberline{\thechapter}#1}%
\else
\addcontentsline{toc}{chapter}{#1}%
\fi
\chaptermark{#1}%
\addtocontents{lof}{\protect\addvspace{10\p@}}%
\addtocontents{lot}{\protect\addvspace{10\p@}}%
\if@twocolumn
\@topnewpage[\@makechapterhead{#2}]%
\else
\@makechapterhead{#2}%
\@afterheading
\fi\clearpage}

\def\@makechapterhead#1{%
\vspace*{50\p@}%
{\parindent \z@ \raggedright \normalfont
    \interlinepenalty\@M
    \Huge \bfseries #1\par\nobreak
    \vskip 40\p@}
    {\normalfont\normalsize\lipsum[2]}
    \tikz[remember picture,overlay]{\node[opacity=0.9,inner sep=0pt,anchor=south] at (current page.south){\includegraphics[width=\paperwidth,height=10cm]{blue.jpg}};}\par%
    {\ifnum \c@secnumdepth >\m@ne
    \vskip 4.2cm\flushright\Huge\color{RoyalRed} \MakeUppercase{\@chapapp}\space%
    \rlap{\scalebox{5}{\thechapter}}
    \par\nobreak
    \fi}
}
\makeatother
\begin{document}
\chapter{Introduction}
\lipsum[1]
\end{document}