Можете попробовать передать имя пользователя и пароль в виде строки python f.
from selenium import webdriver
from selenium.webdriver.common.keys import Keys
from selenium.webdriver.common.alert import Alert
from selenium.webdriver.support.ui import WebDriverWait as wait
from selenium.webdriver.support import expected_conditions as EC
chrome_options = webdriver.ChromeOptions()
driver = webdriver.Chrome(chrome_options=chrome_options,executable_path="C://downloads//chromedriver.exe")
driver.get("url")
wait(driver, 5).until(EC.alert_is_present())
# "Switch" to the Alert browser
alert = Alert(driver)
# Send the username, TAB then password together
alert.send_keys(f'username{Keys.TAB}password')
alert.accept()