As long as you do three things before downloading an app, you don’t need antivirus apps slowing down your phone and taking up valuable space.
1: Only download apps from legal reputable sites like the Google Play Store.
2: Read the comment section. People will scream if there’s something funky going on with an app.
3. Knowledge is power. Read these two forum threads:
Android permissions explained, security tips, and avoiding malware.
Push advertising: notification ads, unwanted shortcuts, browsers redirected.