Mozilla launched Firefox Focus on iOS last year with enhanced privacy features, and now it's available on Android. It was previously available only as source code. This browser doesn't do as many things as the regular Firefox or other browsers, but it does focus on your privacy—presumably that's why they call it Focus.
Firefox focus doesn't have tabs, extensions, or account managers. You just input a URL (or set Focus as your default browser) and the page opens. Ads and trackers are blocked by default, so Focus is really fast. If you do encounter a site that completely disallows access with ad-blockers enabled, you can shut that off in the menu.
At the bottom of the screen is a trash icon, which closes your page and deletes history when tapped. There's also a notification that does the same. Be default, you can't even see your active page in overview or take a screenshot, but that too can be turned off in the settings. If you want to give Focus a shot, it's live in the Play Store and on APK Mirror.