These self forging warheads make top down ATGMs deadly vs anything, including M1s, Leopards, Challengers, and all the Russian and Chinese tanks too. Stopping 15,000 feet per second just isn't happening even with reactive and high tech composite armor combined. The real show stoppers IMO are the sensor fuzed multi round bombs, 32 sub munitions per bomb with some of them, or more, and each forging a 10,000fps+ projectile going straight down on the weakest part of most tanks and APCs. A single F16 4 or even 2 ship can deliver enough in one bomb drop to wipe a brigade off the map now. The Javelin would be an awful weapon to face as a tanker IMO. There could be dozens of them in front of you, you'd never see them in time, and due to their flight profile are very hard to defend against, the Russian tank defense systems are good against wire guided missiles, but the Javelin with that almost vertical attack...not so much I think.
A ton of footage of ATGMs in Syria and Yemen now, there is one video of tank vs tank that I've found with a couple T72s fighting at close range, say 500 yards. That's it. Almost all of the tanks being destroyed on video are from infantry fired ATGMs. I wouldn't feel all that safe in a tank of any nation these days, imagine going up against swarms of well trained combat veteran troops as opposed to guerillas using them now to great effect.
https://www.youtube.com/watch?v=hmFwPyfEAWohttps://defencyclopedia.com/2015/06/12/cbu-105-sensor-fuzed-weapon-usafs-ultimate-tank-buster/