Here is the documentation for this:
https://www.selenium.dev/documentation/webdriver/capabilities/driver_specific_capabilities/#setting-a-custom-profile
I tried this locally and it worked:
EDITED: I’ve changed the code, so there are no deprecation warnings
from selenium.webdriver import Firefox
from selenium.webdriver.firefox.service import Service
from selenium.webdriver.firefox.options import Options
profile_path = r'C:\Users\Administrator\AppData\Roaming\Mozilla\Firefox\Profiles\y1uqp5mi.default'
options=Options()
options.set_preference('profile', profile_path)
service = Service(r'C:\WebDriver\bin\geckodriver.exe')
driver = Firefox(service=service, options=options)
driver.get("https://selenium.dev")
driver.quit()