Align equation environment flushed left

Question

I'm trying to flush an align to the left. So I want to have the following align but no centered:

Here is my code:

\documentclass[11pt,twoside,a4paper]{report}
\usepackage[DM,newLogo]{uaThesis}
\def\ThesisYear{2023}
% optional packages
\usepackage{cite}
\usepackage[new]{old-arrows}
\usepackage{amsmath,amssymb,amsfonts,amsthm}
\usepackage{algorithmic}
\usepackage{graphicx}
\usepackage{calrsfs}
\usepackage{stmaryrd}
\usepackage{unicode-math}
\usepackage{textcomp}

\usepackage{mathabx}
\usepackage{xcolor}
\def\BibTeX{{\rm B\kern-.05em{\sc i\kern-.025em b}\kern-.08em
    T\kern-.1667em\lower.7ex\hbox{E}\kern-.125emX}}
\usepackage{xspace}% used by \sigla
\allowdisplaybreaks[3]
\usepackage{color}
%\usepackage{pdfpages}
\usepackage{amscd}
\usepackage{enumitem}
\usepackage{listings}
\usepackage{cancel}
\usepackage{tikz}
\input xy 
\xyoption{all}
\input{dinmacros.tex}
\usepackage{mathtools}
\usepackage{float}
\usepackage{bookmark}
\usepackage{booktabs}
\usepackage{hyperref}
\usepackage{subfig}
\usepackage{relsize}
\usepackage{tikz-network}
\usetikzlibrary{automata,positioning,calc,shapes.multipart}
\tikzstyle{obj} =[circle, minimum width=0.5cm, minimum height=0.5cm, draw=black]
\overfullrule=0.2mm
\newtheorem{definition}{Definition}
\newtheorem{theorem}{Theorem}
\newtheorem{corollary}{Corollary}
\newtheorem{lemma}{Lemma}
\newtheorem{example}{Example}
%\newtheorem{proof}{proof.}
%\newenvironment{proof}{\noindent \textbf{Proof.}}
\setcounter{tocdepth}{3}
% custom macros (could also be defined using \newcommand)
\def\Sat#1#2{\models^{#1}{#2}}
\def\notSat#1#2{\cancel{\models}^{#1}{#2}}
\def\cat#1{{\sf #1}}
\def\setcat{\cat{Set}}
\def\inst#1{\langle \Sign_{#1},\Sen_{#1},\Mod_{#1},\models_{#1} \rangle}
\def \justif#1{\footnotesize{{\text{#1}}} \}
\def \justleft#1{\footnotesize{{\text{#1}}} \}
\newcommand{\doublef}{f\mspace{-7mu}f}
\newcommand{\doublet}{t\mspace{-3mu}t}
\newcommand{\signature}{\langle \Act, \Prop \rangle}
\newcommand{\signaturee}{\langle \Act', \Prop' \rangle}
\newcommand{\BS}{\boldsymbol{S}}
\newcommand{\Signs}{\Sign_{\BS}}
\newcommand{\Mods}{\Mod_{\BS}}
\newcommand{\Sens}{\Sen_{\BS}}
\newcommand{\modelss}{\models_{\BS}}
\DeclareMathOperator{\upluss}{\scalebox{0.8}{$\biguplus$}}
\DeclareMathOperator{\cupp}{\scalebox{0.8}{$\bigcup$}}
\DeclareMathOperator*{\capp}{\scalebox{0.8}{$\bigcap$}}
\begin{document}
\begin{align}
     M',w \models Sen(\sigma)(\neg \varphi)
     =&\justif{definition of $Sen$}
     & M',w \models \neg Sen(\sigma)(\varphi) &\
     =& \justif{definition of $\models$}
     & \sslash(M',w \models Sen(\sigma)(\varphi)) \
     =& \justif{induction hypothesis} 
     & \sslash (M'|\sigma, w \models \varphi) \
     =& \justif{definition of $\models$}
     & M'|\sigma,w \models \neg \varphi
\end{align}
\end{document}

Thank you