Setting font style for a separate title page

Question

I am writing a report that specify the font styles for title/subtitle different from rest of the text as follows:

Title: Arial Plain font, size 20, with 1.5 line spacing.

Subtitle: Arial Plain font, Size 14, 1.5 line spacing.

Text body: Arial font, size 11, with 1.5 line spacing, text justified (text alignment to both margins);

I created a separate title page, but not sure how to set its formatting styles as specified above.

My code:

1. titlepage.tex

\begin{titlepage}
    \begin{center}
        \vspace*{1cm}
        
        \textbf{Title of Report}    
        
        \vspace{2cm}
        \textbf{Author Name}
        
        \vfill
        Progress report: year 2021
        
        \vspace{0.8cm}
        
        %\includegraphics[]{}
        
        Department Name\\
        University Name\\
        Date
        
    \end{center}
\end{titlepage}

2. main.tex

    \documentclass[11pt]{report}
    \usepackage{fontspec}
    \usepackage{lipsum}
    
    
    \setmainfont{Arial}
    
    \begin{document}
    
    \input{titlepage}
    
    \section{Introduction}
    \lipsum[1]
    
    
    \end{document}

Answer 1

With a 10pt (or 11pt) document font (e.g. \documentclass[11pt]{report}) then a \huge font is 20pt while a \Large font is 14pt.