In general, I block ads across the Android OS by setting my private dns to Adguard's DNS server (I tried including it, but it flagged the post as spam) and then running Blokada with various adblock lists and Adguard DNS.
The Private DNS for Adguard just makes sure that if anything makes an end run around Blokada's pseudo-VPN, it fails because the DNS server will return NXDOMAIN.
It would be possible for Vivaldi for Android to have native adblocking because Opera has it and that's based on Chromium too. Maybe it will be added someday.