How to change Document Title Size in Koma scrbook?

[[extratitleI am using a few a features of Koma script’s maketitle command, namely extratitle, frontispiece and lowertitleback. I want all these features to remain.
I am trying to increase the font size of the main title and subtitle. They should be bigger than the half title on the extratitle page. I do not have an exact requirement as I’ve not been able to play with it. I guess the title needs to be a little larger than Huge.

I have tried several ways but none worked.
First, I tried to use a method of defining a custom size (thanks to Danie Els).

newcommand*{TitleFont}{%
      usefont{encodingdefault}{rmdefault}{b}{n}%
      fontsize{16}{20}%
      selectfont}

setkomafont{title}{TitleFonttextbf} 

I also tried the addtokomafont command, didn’t work either. There was no change to the font size.

Second, I tried the titling package:

usepackage{titling}

pretitle{begin{center}LARGE} 
title{GOOD STUFF}
posttitle{parend{center}vskip 0.5em} 

Also, didn’t work. It lost the earlier pages.

I also tried to define my own titlepage using the titlepage enviroment, but maketitle insists that title is defined.

begin{titlepage}
    vspace*{4baselineskip}
    begin{center}
        usekomafont{title}huge
        hspace*{0.36in}
        textbf{Huge GOOD STUFFnewline}
        hspace*{0.2in}
        textbf{Large Reconciling Your Mama and Your Papa}
        title{GOOD STUFF}
        subtitle{Reconciling Your Mama and Your Papa}
        
        vfill
        Centre of The Universe %Jack edit6, replaced 'newline with 
        The University of Uncommon Sense
        2021
    end{center}
end{titlepage}

I have attached an image as to how the first few pages should look. I’ve spent hours trying to find out how to increase with title size without losing the other features. I’ve read the KOMA guide, the Mittelbach LaTeX guide and googled but no luck.

And the MWE:

documentclass[titlepage=firstiscover,size=160mm:234mm,DIV=calc]{scrbook} 

usepackage{bigstrut}
usepackage[T1]{fontenc} 
usepackage{comment}
usepackage{txfonts} 
usepackage{upgreek} 
usepackage[utf8]{inputenc} 
usepackage{CJKutf8} 
usepackage{hyperref} 
usepackage{blindtext}

newcommand*{TitleFont}{%
    usefont{encodingdefault}{rmdefault}{b}{n}%
    fontsize{56}{20}%
    selectfont}

setkomafont{title}{TitleFont} 

    title{centeringtextbf{GOOD STUFFnewline}} 
    subtitle{Reconciling Your Mama and Your Papa} 
    author{Jack} %Jack edit4
    publishers{Centre of The Universe 
        The University of Uncommon Sense
    2021} %Jack edit5
    date{} %Jack edit4


begin{document}

frontmatter   

extratitle{   
    vspace*{4baselineskip}
        begin{center}
            usekomafont{title}huge
            hspace*{0.36in}
            textbf{Huge GOOD STUFFnewline}
            hspace*{0.2in}
            textbf{Large Reconciling Your Mama and Your Papa}
            title{GOOD STUFF}
            subtitle{Reconciling Your Mama and Your Papa}
        end{center}
    vspace*{2baselineskip}
    blindtext newline
    vspace*{baselineskip}
    
    textbf{Author Name} blindtext
}

 % jacked 03 March to add CBS Publications
frontispiece{ 
    parindent=0pt
    setlength{parskip}{5pt}
    centeringtextbf{Large Publication Series}
    begin{flushleft}
        
        textbf{Scholars}
        
        textit{xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx} 
        yyyyyyyyyyyyyyyyyy
        
        textit{xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx} 
        yyyyyyyyyyyyyyyyyy
        
        textit{xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx} 
        yyyyyyyyyyyyyyyyyy
        
        textit{xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx} 
        yyyyyyyyyyyyyyyyyy
        
        textit{xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx} 
        yyyyyyyyyyyyyyyyyy
        
    end{flushleft}
}

begin{comment}

begin{titlepage}
    vspace*{4baselineskip}
    begin{center}
        usekomafont{title}huge
        hspace*{0.36in}
        textbf{Huge GOOD STUFFnewline}
        hspace*{0.2in}
        textbf{Large Reconciling Your Mama and Your Papa}
        title{GOOD STUFF}
        subtitle{Reconciling Your Mama and Your Papa}
        
        vfill
        Centre of The Universe %Jack edit6, replaced 'newline with 
        The University of Uncommon Sense
        2021
    end{center}
end{titlepage}

end{comment}
lowertitleback{    % jacked 26 Feb to add copyright-publisher's block
    
    begin{flushleft}
        
        Published in by School of Hard Knocks
        The University of Uncommon Sense
        2021
        vspace*{baselineskip}
        © Centre of The Universe,
        The University of Uncommon Sense
        All Rights Reserved
        vspace*{baselineskip}
        ISBN: 978-999-99999-9-2 (Hardcover)
        ISBN: 978-999-99999-9-9 (e-book)
        
    end{flushleft}
}

maketitle 

begin{center}
    noindent
    What is to prevent us, then, from hiding this under my pillow?
    
    Arisnotle, 
end{center}


pagebreak

end{document}

Sorry, but the images didn’t upload/appear how’d I’d expected.