You're going overboard with the brackets. You don't need anywhere near as many.
Here's what I'd do in the same situation where I want a working area in the closet. The top is a single layer of GOOD 3/4" plywood. Or if you wish double it to make it 1 1/2 thick. But really I think that is overkill. I'm showing in the sketch below a 16 inch wide top for the reason that all presses when mounted stick out from the front edge by some amount and you want to close the door with the press still mounted. My Dillon 550 sticks out 6.5" and the Hornady single stage sticks out about 4.5". So you can't really go much wider than 16".
My sketch shows a 2x4 cleat screwed to the wall at the stud locations. Then the top is screwed down to that cleat. The front is a 2x4 apron with two 2x4 legs screwed to the apron and extending to the floor.
To avoid the carpet producing any give in the front edge the inset shows my suggestion for screwing 4 drywall screws through the carpet and into the plywood floor underneath. Leave then sticking up enough that the heads are more or less even with the top of the carpet knap and level them with each other. The ends of your legs will rest on the set of 4 (or 6) screw heads and be held in place by a smaller than you show flat L bracket. Something about 2.5" is fine. It's only there to keep the leg from being kicked away.
Because the top is so narrow to let the door close with the press mounted it does not need to be all that thick. You may elect to make the top wider other than a cut away that goes down to the 16'ish inch top width at the location of the press. That's up to you.
There are no angle brackets at the top because it's already held very nicely by the cleat on the wall and the apron and legs. Once the feet of the legs are secured with the angle bracket and to the wall cleat that bench isn't going anywhere.
The screws you need for all this are #8x3 for going through the 2x4's and into the wall or the other 2x4. They are overkill for holding the plywood down but they'll work fine instead of buying another size. And a few #6x1 1/4 for the feet areas of the two legs.
All those angle brackets you show are not needed because fixing things to the wall and floor locks everthing solidly. The only brackets you need are a couple of the 2.5" flat steel brackets to keep the feet of the front legs from being kicked out of place.