1 - Your spray pattern is fucking horrible in this clip, and because you were moving in your first few bullets, the pattern is fucked... You were on the left side of his bullets when your bullets were going left (Missing him)... And then you moved over to other side of the body when the bullets were going right of your crosshair (Missing him). There's at max 1 bullet that shouldn't have missed that did, not an issue... The only issue here is that you suck... Stop moving and shooting
2 - January 2018, the time of which the jump crouch bug was a thing, is there any clip that shows who killed you? It might be that a guy used to bug to jump over the wall without you seeing him and got you with a lucky one, don't reply to this unless you actually have a clip... I'm not going to just trust your word on it
3 - The first bullet you fired was when you were moving and you were shooting to fast, where you see the bullet land behind the head, it doesnt actually land there because the server and client were not 100% in sync back in this version of CS, btw don't make me out to be the clueless one when you've put a fucking clip in here that is almost a year old when you're talking about how it's a problem now, there was many fixes on hitboxes since then.
4 - Where's the proof that he was even moving at full speed? He may have been holding an angle a little to the right then decided to peek out, I'm not sure if you've noticed this, but as soon as you hit the strafe key, you're player doesn't move 240u/s instantly... You might just be overlooking it
5 - This is called counter strafing, your weapon can be accurate from like 0-30 u/s (Just a guess, but it certainly doesn't require the player to be stationary). So what if he slides? It's not like he's invincible when he's sliding, just shoot him - I guarentee that you look like this when you're moving at times too, so it's not an unfair advantage... It's an extremely minor problem that valve shouldn't bother working on, and again from half a year ago
To summerise, there is literally 0 clips that are in the current version of csgo, and all half a year ago, ever since valve has been doing minor updates to the source engine that may have actually fixed a lot of this, and these clips aren't even problems, none of them are game breaking and you're picking at the game rather than yourself, trust me - This is bad, you're throwing clips out there when you are doing dumb shit like running and shooting and then blaming the game for your silver gameplay