Different linespacing between title page and sections

I need my document to have a linespace of 2, but not on the title. I tried customizing the baselineskip command, but this changes the line spacing also on the title. I also tried fontsize{}{} and linespread{} on the title, but they have no effect in the line spacing. How can I have linespacing 2 only in the sections but not in the rest of the document (title, references, table of contents etc)?

documentclass{article}
usepackage[utf8]{inputenc}
usepackage{graphicx}
usepackage[a4paper, total={6in, 9in}]{geometry}
renewcommand{baselinestretch}{2}




begin{document}
begin{titlepage}
    begin{center}
        vspace*{1cm}
        Huge
        textbf{Did IMF policies improve the economic conditions of low-income countries?}
       
        vspace{0.5cm}
       
        LARGE
        The Ghanaian case study
            
        vspace{1.5cm}
            
        textbf{Author Name}
            
        vfill
            
        A thesis presented for the degree of
        Doctor of Philosophy
            
        vspace{0.8cm}
            
            
        Large
        Department Name
        University Name
        Country
        Date
            
    end{center}
end{titlepage}


section{Introduction}
Contrary to popular belief, Lorem Ipsum is not simply random text. It has roots in a piece of classical Latin literature from 45 BC, making it over 2000 years old. Richard McClintock, a Latin professor at Hampden-Sydney College in Virginia, looked up one of the more obscure Latin words, consectetur, from a Lorem Ipsum passage, and going through the cites of the word in classical literature, discovered the undoubtable source. Lorem Ipsum comes from sections 1.10.32 and 1.10.33 of "de Finibus Bonorum et Malorum" (The Extremes of Good and Evil) by Cicero, written in 45 BC. This book is a treatise on the theory of ethics, very popular during the Renaissance. The first line of Lorem Ipsum, "Lorem ipsum dolor sit amet..", comes from a line in section 1.10.32.

The standard chunk of Lorem Ipsum used since the 1500s is reproduced below for those interested. Sections 1.10.32 and 1.10.33 from "de Finibus Bonorum et Malorum" by Cicero are also reproduced in their exact original form, accompanied by English versions from the 1914 translation by H. Rackham.

end{document}

% spacingprob.tex  SE 579696

documentclass{article}
usepackage[utf8]{inputenc}
usepackage{graphicx}
usepackage[a4paper, total={6in, 9in}]{geometry}
%renewcommand{baselinestretch}{2}

begin{document}
begin{titlepage}
    begin{center}
        vspace*{1cm}
        Huge
        textbf{Did IMF policies improve the economic conditions of low-income countries?}
       
        vspace{0.5cm}
       
        LARGE
        The Ghanaian case study
            
        vspace{1.5cm}
            
        textbf{Author Name}
            
        vfill
            
        A thesis presented for the degree of
        Doctor of Philosophy
            
        vspace{0.8cm}
            
            
        Large
        Department Name
        University Name
        Country
        Date
            
    end{center}
end{titlepage}
% thebaselineskip % prints the default baselineskip 

% the ToC, etc

setlength{baselineskip}{24pt}
section{Introduction}
Contrary to popular belief, Lorem Ipsum is not simply random text. It has roots in a piece of classical Latin literature from 45 BC, making it over 2000 years old. Richard McClintock, a Latin professor at Hampden-Sydney College in Virginia, looked up one of the more obscure Latin words, consectetur, from a Lorem Ipsum passage, and going through the cites of the word in classical literature, discovered the undoubtable source. Lorem Ipsum comes from sections 1.10.32 and 1.10.33 of "de Finibus Bonorum et Malorum" (The Extremes of Good and Evil) by Cicero, written in 45 BC. This book is a treatise on the theory of ethics, very popular during the Renaissance. The first line of Lorem Ipsum, "Lorem ipsum dolor sit amet..", comes from a line in section 1.10.32.

The standard chunk of Lorem Ipsum used since the 1500s is reproduced below for those interested. Sections 1.10.32 and 1.10.33 from "de Finibus Bonorum et Malorum" by Cicero are also reproduced in their exact original form, accompanied by English versions from the 1914 translation by H. Rackham.

clearpage
setlength{baselineskip}{12pt}

% references, etc
end{document}