If the rumors about Pancada going on sentinel are true, why? Why not have Marved on sentinel instead? Isn't Pancada better at smokes?

Regardless of your choice, it will be able to run Valorant at max graphics easily, so it doesn't really matter. In general though:

1. Yes
2. Yes
3. I don't have any personal experience with them, but it should be fine because I haven't heard of any huge scandals with them/
4. I'm not too sure about this, I'd recommend going on a tech forums or discord server like https://pcpartpicker.com and ask them about this.

You did not just say Xeppaa