@Jo Android 9 and upwards should have a setting in Settings → Network & internet → Advanced → Private DNS
@Jo https://quad9.com is pretty good, you can opt out of the security features if you wanna https://quad9.com/faq/#Is_there_a_service_that_Quad9_offers_that_does_not_have_the_blocklist_or_other_security
@Jo (note that Android needs DNS-over-HTTPS)