to expand on what khizaimar86 said, the best solution is to use opera for android or opera beta with the off-road feature enabled.
this gives you at least some of the speed and data usage improvements of opera mini without blocking embedded videos.

those browsers where made prior to Adobe discontinuing flash mobile, and chose not to remove support.

it's unlikely opera will ever allow flash player because it hasn't had a proper update in years.
it's discontinued, so no more security flaws are being fixed.

How to disable ads in Opera? Any alternate command for accessing "opera:config" power user settings?

install adguard and enable it in VPN mode(default setting)

adguard is free over 3/4g too, but only if you use VPN mode.

mini got fullscreen mode a while ago, why isn't this available in opera beta yet?
it's the one thing keeping me from switching over, and I've been waiting(and asking) for it for years.

Dicemaster, hah noob, he doesn't know how how to access Fullscreen in Opera for Android! Simple: Settings > Tab Layout (Classic) > Fullscreen button in corner... Anyway I think Pulsing Animation is for address bar w00t!

that's not fullscreen.
sure it hides the navigation buttons, but the android notification bar is still visible, and this only works in landscape mode.
also, this same "fullscreen" mode with visible notification bar is activated automatically in any other layout if you scroll down.

what I'm asking for is the fullscreen mode present in opera mini beta and the old opera mobile, which hides the notification bar.

an antivirus that interacts with your browser is pointless on android.
any potential malware would have to go through the package installer to install itself, which is where it's already checked by any antivirus you might be running or the "verify apps" feature of the Google play services.

I found another thing missing.
opera doesn't allow windowed mode on samsung devices.
adding this should be as simple as adding a line to the manifest file saying it's ok to open opera in windowed mode, the rest is all managed by touchwiz.

Google doesn't allow apps that interfere with the function of other apps(like blocking in-app ads)
they don't mind browsers that block ads for security, speed, or to conserve power.

mini got fullscreen mode a while ago, why isn't this available in opera beta yet?
it's the one thing keeping me from switching over, and I've been waiting(and asking) for it for years.

opera doesn't choose which version it loads, the webserver does that.
opera tries to control this by saying "I'm opera for Linux desktop computers" if you enable desktop mode, but many websites either incorrectly list opera for Linux as mobile browser(send an angry letter to whoever runs the website if this happens) or they use your screen size to determine what they think is the best layout.

private navigation is available through the overflow(3 dots) button in the tab switcher, or by long-pressing the new tab button if you use the tablet layout.

an easy method of switching between mobile and desktop mode is by setting it to desktop mode, and switching off-road on when you want the mobile page.
off-road always loads mobile pages.