In the first infinity war movie, corvus was going toe to toe with vision but was struggling against widow and cap, cull obsidian was handling the hulk buster just fine. Proxima could have beaten widow, cap and falcon by herself and ebony maw was pretty confident he could handle iron man by himself easily
Then came endgame, thanos and the black order already saw the future, so you would have to think that they would be shown justice, except the russos thought otherwise, cull obsidian didnt even last for a minute, PIS that falcon and giant man are enough to hurt him, hes suppose to be > hulk buster, ebony maw could have easily been utilised better especially against the heroes. Corvus again is shown the ultimate disrespect as he is now killed with his own blade again. Seriously why did thanos choose the black order if they are this weak? Do the russos clearly not care?