Python - how to convert .txt to LaTeX?

Question

I am currently performing multiple transformations from a .txt file to LaTeX using the following code:

from pylatex import Document, PageStyle, LineBreak, Section, Subsection, Math, Alignat, LargeText, Center, MediumText
from pylatex.utils import bold, italic, NoEscape
import os as os

class Math_LaTeX ():
    def __init__(self, doc):
        #---Inicializamos---
        self.doc = doc

        #---De aqui sacamos las ecuaciones del archivo .txt---
        equations = self.Read()

        #---Creamos el documento Latex---
        self.Create(equations)

        #---Creamos el PDF---
        self.doc.generate_pdf(filepath = TituloPDF, clean_tex = False, compiler = 'pdflatex')

    def Read(self):
        data = open(archivotxt, 'rt')
        equations = data.readlines()
        eqs = []
        for eq in equations:
            eqs.append(' '.join([line.strip() for line in eq.strip().splitlines()]))
        return eqs

    def Create(self, equations): 
        for eq in equations:
            with self.doc.create(Alignat(numbering = False, escape = False)) as math_eq:
                math_eq.append(eq)        
geometry_options = {
        "head": "0.5cm",
        "left": "0.5cm",
        "right": "0.5cm",
        "bottom": "2.5cm"
        }
doc = Document(geometry_options = geometry_options, inputenc = 'utf8')
Math_LaTeX(doc)
if os.path.exists(archivotxt):
    os.remove(archivotxt)
else:
    print("El archivo no existe") 

This is what i get:

\documentclass{article}%
\usepackage[T1]{fontenc}%
\usepackage[utf8]{inputenc}%
\usepackage{lmodern}%
\usepackage{textcomp}%
\usepackage{lastpage}%
\usepackage{geometry}%
\geometry{head=0.5cm,left=0.5cm,right=0.5cm,bottom=2.5cm}%
\usepackage{amsmath}%
%
%
%
\begin{document}%
\normalsize%
\begin{alignat*}{2}%
{\left( 3 \right) {x_{1}} +\left( -0.1 \right) {x_{2}} +\left( -0.2 \right) {x_{3}} = {7.85} }%
\end{alignat*}%
\begin{alignat*}{2}%
{\left( 0.1 \right) {x_{1}} +\left( 7 \right) {x_{2}} +\left( -0.3 \right) {x_{3}} = {-19.3} }%
\end{alignat*}%
\begin{alignat*}{2}%
{\left( 0.3 \right) {x_{1}} +\left( -0.2 \right) {x_{2}} +\left( 10 \right) {x_{3}} = {71.4} }%
\end{alignat*}%
\text{ -------------------------------------------------------------------------- }%
\end{alignat*}%
\begin{alignat*}{2}%
\text{Entonces la solución estaría dada por:}%
\end{alignat*}%
\begin{alignat*}{2}%
X = \begin{bmatrix}  x_{1} \\  x_{2} \\  x_{3} \end{bmatrix}  = \begin{bmatrix}  3.0 \\  -2.5 \\  7.0 \end{bmatrix}%
\end{alignat*}%
\end{document}

However, I cannot customize various aesthetic aspects of the final PDF, so I decided to create a text file with all the specifications through Python.

\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage[spanish]{babel}
\usepackage[T1]{fontenc}
\usepackage{lmodern}
\usepackage{textcomp}
\usepackage{lastpage}
\usepackage{geometry}
\geometry{head=2.5cm,left=2.5cm,right=2.5cm,bottom=2.5cm}
\usepackage{amsmath}
\usepackage{fancyhdr}

\pagestyle{fancy}
\lhead[]{Ejercicio 01}
\begin{document}


$ {\left( 3 \right) {x_{1}} +\left( -0.1 \right) {x_{2}} +\left( -0.2 \right) {x_{3}} = {7.85} } $ 

$ {\left( 0.1 \right) {x_{1}} +\left( 7 \right) {x_{2}} +\left( -0.3 \right) {x_{3}} = {-19.3} } $

$ {\left( 0.3 \right) {x_{1}} +\left( -0.2 \right) {x_{2}} +\left( 10 \right) {x_{3}} = {71.4} } $


\newpage
\lhead[]{Ejercicio 02}

$ k = {2},x^{\left( {2} \right)}={\begin{bmatrix}  2.61667 \\  -2.79452 \\  7.00561 \end{bmatrix} }$%


$ \text{ -------------------------------------------------------------------------- } $%


\end{document}

This writes it to the .txt file without any problem, but what I need is for this new txt file to be transformed into a PDF using a LaTeX compiler, all from Python as above and that's what I don't know how to do.

I would greatly appreciate your help