How to right align a footline in beamer which is of reduced length

Question

I am creating a presentation in beamer with a few sections and subsections. I am using the Bergen theme. I want to add footline in my slides. Taking the idea from this answer, I made the following MWE:

\documentclass[aspectratio=169]{beamer}
\usetheme{Bergen}
\usefonttheme{serif}
\usecolortheme{wolverine}
\usepackage{etoolbox}
\usepackage{ragged2e}
\def\insertauthorindicator{compiled by}
\def\insertinstituteindicator{}
\def\insertdateindicator{}
\setbeamertemplate{navigation symbols}{}
\setbeamertemplate{footline}{%
    \begin{beamercolorbox}[colsep=1.5pt, wd=.75\paperwidth]{upper separation line head}
    \end{beamercolorbox}
    \begin{beamercolorbox}[wd=.75\paperwidth]{section in head/foot}
        \vskip2pt\insertnavigation{.75\paperwidth}\vskip2pt
    \end{beamercolorbox}%
    \begin{beamercolorbox}[colsep=1.5pt, wd=.75\paperwidth]{lower separation line head}
    \end{beamercolorbox}
}
\setbeamercolor{section in head/foot}{fg=yellow, bg=black}
\setbeamercolor{subsection in head/foot}{fg=white, bg=blue!90!black}


\setbeamercolor{author}{fg=violet}
\setbeamercolor{date}{fg=violet}

\title{Title}
\subtitle{Subtitle}
\author[]{XYZ}
\date[\today]{\today}
\begin{document}
    \begin{frame}
        \titlepage
    \end{frame}
\section{Section 1}
    \begin{frame}
        \LARGE Section 1
    \end{frame}
\subsection{Subsection 1.1}
    \begin{frame}
        Content
    \end{frame}
    \begin{frame}
        Content
    \end{frame}
\subsection{Subsection 1.2}
    \begin{frame}
        Content
    \end{frame}
\end{document}

I need to make the following changes in the output:

1. The footline should be right aligned, i.e., it should occupy the rest of the right space after the sidebar. The existing appearance of the sidebar must not change.
2. The footline should start appearing after the titlepage.
3. Only sectionheads should be displayed in the footline. For the subsectionheads, I only need a bullet or a circle. I do not want any frame indicator as is present there.
4. The bullets for the subsections should be placed horizontally in the footline.
5. The short sectionheads should appear in the footline.

Please help.

Answer 1

1. The footline should be right aligned, i.e., it should occupy the rest of the right space after the sidebar. The existing appearance of the sidebar must not change.

you can add \hfill before the beamer box

However you won't be happy with the result. By default, the sidebar does not go all the way to the bottom of the page, so there will an ugly white gap.

Instead of the normal sidebar, you could use

\setbeamertemplate{sidebar canvas left}[vertical shading][top=orange!75!white,bottom=orange!75!white]

which will reach all the way to the bottom of the page

2. The footline should start appearing after the titlepage.

either use a plain frame for the title page, or temporarily redefine the footline template

4. The bullets for the subsections should be placed horizontally in the footline.

use the compress option

5. The short sectionheads should appear in the footline.

The navigation bar will automatically show the short version of teh section name if present

\documentclass[aspectratio=169,compress]{beamer}
\usetheme{Bergen}
\usefonttheme{serif}
\usecolortheme{wolverine}
\usepackage{etoolbox}
\usepackage{ragged2e}
\def\insertauthorindicator{compiled by}
\def\insertinstituteindicator{}
\def\insertdateindicator{}
\setbeamertemplate{navigation symbols}{}
\setbeamertemplate{footline}{%
    \hfill\begin{beamercolorbox}[wd=.75\paperwidth]{section in head/foot}
        \vskip2pt\insertnavigation{.75\paperwidth}\vskip2pt
    \end{beamercolorbox}%
}
\setbeamercolor{section in head/foot}{fg=yellow, bg=black}
\setbeamercolor{subsection in head/foot}{fg=white, bg=blue!90!black}

\setbeamertemplate{sidebar canvas left}[vertical shading][top=orange!75!white,bottom=orange!75!white]

\setbeamercolor{author}{fg=violet}
\setbeamercolor{date}{fg=violet}

\title{Title}
\subtitle{Subtitle}
\author[]{XYZ}
\date[\today]{\today}
\begin{document}
{
\setbeamertemplate{footline}{}
    \begin{frame}
        \titlepage
    \end{frame}
}
\section[Sec1]{Section 1}
    \begin{frame}
        \LARGE Section 1
    \end{frame}
\subsection{Subsection 1.1}
    \begin{frame}
        Content
    \end{frame}
    \begin{frame}
        Content
    \end{frame}
\subsection{Subsection 1.2}
    \begin{frame}
        Content
    \end{frame}
\end{document}