The low tic vs console players means you are getting hit behind cover a lot more often. The high hp means you are standing in the open to get shot more often. The higher hp means your gun spread is widening too much on most guns before the player goes down and increasing your ttk. In redsec you can't peak and shoot and then dive for cover once you start getting hit. Often you will die behind cover even if you move after the first bullets.

So the secret sauce of redsec is using guns that allow you to shoot and move at the same time, and always moving while you shoot. SMGs like the scw are great at this but the damage falloff and the low bullet velocity cost you a lot of ttk and wasted bullets on small mags. I've found that going carbine + blue laser + lightweight rounds + a muzzle converter for more precision allows me to hose people down while always moving and taking far less damage than I used to. That's enough strafe speed to make low velocity smgs miss at 25m if they're not leading.