Horizontal baseline after chapter number, stretched to right margin, above chapter title

Question

The question may look lengthy, but it is what I need.

I want horizontal line beside chapter number and the vertical position of the line should be on lower. It should be like this

1___

In this link, the vertical position is on middle (1---)

Then, the horizontal line should be stretched to right margin. The previous link shows it.

Then, the chapter title should be below the chapter number, like this

1___
Chapter title

The most important, I want the format of the chapter number and chapter title follow previous (origin) definition. On this link, the code introduces a lot of changes to the chapter number and chapter title. I just want the line.

The line thickness should be standard (1pt).

\documentclass[twoside]{book}

\usepackage[paperheight=9.72in,paperwidth=6.85in]{geometry}

\usepackage{amsmath}
\usepackage{amsthm,mathpazo}

\makeatletter
\def\@makechapterhead#1{%
  \vspace*{10\p@}%
  {\parindent \z@ \raggedright \normalfont
    \ifnum \c@secnumdepth >\m@ne
      \if@mainmatter
        \huge\bfseries \@chapapp\space \thechapter
        \par\nobreak
        \vskip 20\p@
      \fi
    \fi
    \interlinepenalty\@M
    \Huge \bfseries #1\par\nobreak
    \vskip 40\p@
  }}
\def\@makeschapterhead#1{%
  \vspace*{10\p@}%
  {\parindent \z@ \raggedright
    \normalfont
    \interlinepenalty\@M
    \Huge \bfseries  #1\par\nobreak
    \vskip 40\p@
  }}
\makeatother

\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage[symbolmax,defaultmathsizes]{mathastext}

\begin{document}

\chapter{Chapter title}

\end{document}

For the MWE, I tried change and combine the codes on the links but I am not familiar on TikZ and the codes introduce changes that I do not want.

Answer 1

Do you want something like this?

\documentclass[twoside]{book}
\usepackage[paperheight=9.72in, paperwidth=6.85in]{geometry}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage[symbolmax,defaultmathsizes]{mathastext}

\usepackage{amsmath}
\usepackage{amsthm,mathpazo}
\usepackage{titlesec, linegoal}
\usepackage{lipsum}

\titleformat{\chapter}[display]{\Huge\bfseries}{\huge\chaptername~\thechapter \rule[-0.5ex]{\linegoal}{1pt}}{2ex}{\filcenter}
\titlespacing*{\chapter}{0pt}{2ex}{8ex}

\begin{document}

\chapter{Chapter title}

\lipsum[1]

\end{document}