Here at the very start of the round, you can see that you bought head armor (not really needed but that's ok). What is wrong is you don't buy any smokes, grenades, flashes, or incendiary with the extra $1500 you have. With $1500 you can afford 1 smoke, 1 fire, and 2 flashes.
The smoke can be used to give you some "cover" and/or stop them from rushing for a little bit to buy some time for your team to get repositioned for the push. Smokes last for ~17 seconds if I remember. That's quite a while. Also, a fire would also stop them from going to a certain spot or also rushing in. Usually people don't run through fire or run into it because they don't want to take the damage. And flashes, well they blind people pushing in so you can peek out and shoot at them and then take cover after getting a pick or two.
The second mistake of this round is peeking a new angle that isn't clear while you're still reloading which of course, a T happens to push this angle just at the right time and you're not able to shoot back at him because you're still reloading. #csgotiming
When you reload, try to take cover as best as possible until you're done reloading then peek out. If you peek out while still reloading, most likely you'll get shot down before you can shoot back. Especially at higher ranks when their aim is a bit better.
Happens here again in the next round you show us. You kill two of them, and then reload and decide to run out of quad opening yourself up from being shot at from A main and Squeakyish.
Your teamate is barely getting onto catwalk and you have no one sitting truck to watch anyone pushing out A main. So you should be aware that it's possible there is another person so unless you were rotating to B and you know there is no chance of anyone being A you shouldn't really just run out in the open while still reloading.