Video I guess sums up your in game decision making, skill and especially comms in game.
I would bet my money on that some of this great 3stack that just wiped 2 squads got shot while heads and toes in lootboxes :D
Also if you had Wattson Gen up I would assume Caustic ult should have been destroyed by it -> either Ult actually was not on you and you just walked into gas-fight / panicked or there is major bug in game where Wattson ult is not destroying Caustic ult nade.
Caustic still is overall average at best, gas finally hits decently for people to double-check if they want to walk in and fight, yet when it is 2v3 or 1v3 I always still go straight in as after removal of slow effect and making gas more transparent, fighting in it for a short time is still very viable tactics. Slow effect needs to be returned! And then Caustic can be again relevant.
Nowadays people play him what I feel for fun more so than for competitive reasons. I can hardly imagine besides Newcastle that you can play someone defensive minded - Rampart, Wattson, Catalyst, Gibi, even Bang is sort of irrelevant.