Piling sanction on top of sanction on top of sanction does not work. I think if you say that you are going to take away the game from 4-8pm, then that is the sanction. Its OK if he kicks off, the sanction holds. As you have seen, increasing the sanction only leads to worse behaviour.
I think if you look at natural vs logical consequences as an alternative.
A natural consequence is something that happens without any intervention from you.
Natural consequences for not getting up and going to school is that the next day you have to explain yourself to the school, who will already know that you refused to come in.
Logical consequence - this is something imposed by your that is logically linked to the issue.
The natural and logical consequence of him teasing your other child to the point of meltdown is that whatever the plan was for that day, its gone out the window while everyone deals with the melting one. As in "oh what a shame, we cant go to the park now because billy is really upset. " Or "sorry I don't have time to switch the internet back on, I am dealing with Billy. It seems you wanted to upset him and call him names, so I wonder if you really didnt want to go on the internet after all. Oh you did? Well thats very confusing because you knew what would happen if you wound up your brother."
Or "Im sorry I cant look for your football boots, I am dealing with Billy."
I would also implement a screen bar with immediate effect from 7am to 6pm, school days, for all kids. This is not a sanction, its stating that there is a problem, people are becoming a little it crazy because they arent getting out in the fresh air and running about, so you've decided that this is going to help everyone get out in the fresh air. Not negotiable. Staying at home all day is a lot more boring if there is nothing to watch or do.
The reaction will be severe for the first week, batten down the hatches. but then will become the new normal.