As someone being bilingual en/de and my family being primarily pl/de:
I will either manually remux my own from torrent/usenet releases or (usually for shows) usually just download the german version.
Usually the uploaders include the english track anyway.
Regarding your question for multilingual radarr/sonarr: https://trash-guides.info/Radarr/radarr-setup-quality-profiles-french-en/
Just replace fr with language of choice :)