您可以使用text_to_be_present_in_element_attributeexpected_conditions。
下面的代码是有效的：

from selenium import webdriver
from selenium.webdriver.chrome.service import Service
from selenium.webdriver.chrome.options import Options
from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.common.by import By
from selenium.webdriver.support import expected_conditions as EC

options = Options()
options.add_argument("start-maximized")

webdriver_service = Service('C:\webdrivers\chromedriver.exe')
driver = webdriver.Chrome(options=options, service=webdriver_service)
wait = WebDriverWait(driver, 60)

url = "https://demoqa.com/progress-bar"
driver.get(url)

wait.until(EC.element_to_be_clickable((By.ID, "startStopButton"))).click()
wait.until(EC.text_to_be_present_in_element_attribute((By.CSS_SELECTOR, '[role="progressbar"]'),"aria-valuenow","70"))
wait.until(EC.element_to_be_clickable((By.ID, "startStopButton"))).click()

UPD

对于第二个页面，以下代码同样有效：

from selenium import webdriver
from selenium.webdriver.chrome.service import Service
from selenium.webdriver.chrome.options import Options
from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.common.by import By
from selenium.webdriver.support import expected_conditions as EC

options = Options()
options.add_argument("start-maximized")

webdriver_service = Service('C:\webdrivers\chromedriver.exe')
driver = webdriver.Chrome(options=options, service=webdriver_service)
wait = WebDriverWait(driver, 60)

url = "http://uitestingplayground.com/progressbar"
driver.get(url)

wait.until(EC.element_to_be_clickable((By.ID, "startButton"))).click()
wait.until(EC.text_to_be_present_in_element_attribute((By.CSS_SELECTOR, '[role="progressbar"]'),"aria-valuenow","75"))
wait.until(EC.element_to_be_clickable((By.ID, "stopButton"))).click()