The thing is if you don't install sketchy apps you probably don't need a antivirus, saying that I do have Bitdefender on my family members android devices it more just incase they install crap by mistake plus you web browsering is protected by Bitdefender web protection plus it uses my spare slots up on my Bitdefender family pack 15 devices I got cheap.
Ads blocking wise adguard is good if SSL intercept is on, but DNS level ad blocking is going to getting more and more ineffective as time go on as more and more sites and apps are getting wiser and starting to use the ad domain for non ad content that is needed for it work.
I use adguard at home, I've noticed recently I have to whitelist more and more domains since they are using the domain for tracking/ads for legitimate assets needed for app /website functionality.