Universal PDF converter

I am looking for a help with "any document converter", where any document file [doc, docx, ppt, pptx] will be converted to pdf. DOCX and PPTX are easy to handle with python libraries, but DOC and PPT is a bit tricky.
The answers I've got 7 month ago was quite a bit hard to deal with. Especially the one with use of Unoconv (now its deprecated and changed to Unoserv).

Initial code example:

import os
import shutil

src = ".../srcpaths"
dst = ".../dstpaths"
ext = ['ppt', 'pptx', 'doc', 'docx']

for root, subfolders, filenames in os.walk(src):
    for filename in filenames:
        if os.path.splitext(filename)[1] in ext:
            shutil.copy2(os.path.join(root, filename), os.path.join(dst, filename))            
        
def ConvertToPDF(ext):
    #some code#

ConvertToPDF('.ppt')
ConvertToPDF('.pptx')
ConvertToPDF('.doc')
ConvertToPDF('.docx')

Solution

Below is my review of solutions and an answer at the end:

1. Pandoc:

requires pdf latex processor
not preserving the shape of files well
loss of formatting
problems with graphics
problems with charts
problems with fonts
low on formats choice

2. Unoconv/Unoserver

hard to install and deal with
requires Libre Office as engine
good conversion results (not perfect)

3. Cloud-based solutions:

not free
not open-source friendly
privacy concerns

4. Google Drive API converter:

using someone’s account
upload document – Convert it – Save it as PDF
privacy concerns

5. LibreLambda

uses Amazon Web Services (AWS)
privacy concerns

Simple solution:

Use the software straightly by running it in a cmd subprocess.

Needs: installation of LibreOffice. Biggest advantage: can run both on Windows and Linux (should be modified for linux)

Here is my Python code for Windows:

import os
import subprocess

# path to the engine
path_to_office = r"C:\Program Files\LibreOffice\program\soffice.exe"

# path with files to convert
source_folder = r"C:\ConvertToPDF\input_files"

# path with pdf files
output_folder = r"C:\ConvertToPDF\output_files"

# changing directory to source
os.chdir(source_folder)

# assign and running the command of converting files through LibreOffice
command = f"\"{path_to_office}\" --convert-to pdf  --outdir \"{output_folder}\" *.*"
subprocess.run(command)

print('Converted')

If you can modify it to Linux, please feel free to share your solution