You mentioned Python is not able to download HTML without using external library, but this sample is only using internal library.
$ cat test.py
import urllib.request
data = urllib.request.urlopen("https://google.com")
print(data.read())
Output
$ python3 test.py
b'<!doctype html><html itemscope="" itemtype="http://schema.org/WebPage" lang="en-MY"><head><meta content="text/html; charset=UTF-8" http-equiv="Content-Type"><meta content="/images/branding/googleg/1x/googleg_standard_color_128dp.png" itemprop="image"><title>Google</title><script nonce="J+dyoOcziE1OqkDIbQfsNQ==">(function(){window.google={kEI:\'WI0pYobbAuvd2roPnPGw4AY\',kEXPI:\'0,1302536,56873,6058,207,4804,2316,383,246,5,1353,4014,1237,1122516,1197754,647,22,380067,16115,28684,17572,4859,1361,9291,3028,17580,4020,978,13228,3847,4192,6430,14762,7979,5081,1593,1279,2451,291,149,1103,840,1983,214,4100,3514,606,2023,2297,14670,3227,2845,7,17450,8101,8219,1851,1575