What you're missing is, that doesn't necessarily count for a whole lot, as troops & countries learn quickly (as if to say the US & UK aren't prepared for anything Russia could ever throw at them - they totally are). Troops learn, they adapt, they get better under the circumstances they find themselves in. WWI, the Americans came in green as fuck, not knowing a thing, had to be shown the ropes by the Brits & French & Australians. Thing is, like 8-10 weeks later they were fucking up Germans left right & centre with superior numbers & gear and a lack of fatigue. That applies to war in general, we're seeing it right now: Russia fucking sucked in the opening year of this war - they've turned that around and are now pretty much man-for-man equal with the Ukrainians. This stuff is fluid.
As for "the western equipment hasn't done jackshit" part? Okay, cool, guess we'll just stop sending it. Ukes, you've apparently got this, don't need our toys anymore. Godspeed, you're on your own.
Yeah, you don't believe that. Any vehicle is vulnerable at a point, there was never any guarantee Abrams & Bradleys were going to turn the war in the Ukrainian's favor (I'd even go as far as saying no one in the west actually believed it *would*). They were still a hell of a lot better off having them than not, because their own stuff is...Ukrainian.