There is no "same block" you could call it the "next block" and that's the closest to simplicity it gets, otherwise, technically, every share on its own is an attempt to solve a block, your miners are randomly generating a "number" that could make a valid block or not, if they manage to hit a valid block they would broadcast it to the network and it gets the block number of the previous block number + 1.

The fact that blocks are in a chain and block 1000 can't be generated before 999 is, doesn't mean that after block 999 everyone was working on the same block, yes everyone was working on block number 999+1 but that block is different for every miner, I am trying to make this look and seem as simple as I can, but somethings are not that simple to understand without having a prior knowledge of the basics, and all these online articles that describe bitcoin mining as "solving complex math problems" make things even worse for the average joe to understand what mining actually is.

The simplest analogy I could lay out for you would be to imagine that each miner is a hunter, where millions of miners are hunting in the woods at 12AM, all of those hunters are blind so they can't even see what they are shooting at, there are many animals in the woods, you don't know which one you are going to shoot, you don't even know if you are going to hit any to begin with, of course, the more shots per time unit the more likely you are going to hit one which is why larger miners hit more blocks.

so once a hunter hits a target, he needs to announce it, so he brings the dead animal and ties it to the end of that chain, and the shooting goes on. if two hunters hit two targets at the same time, the one who manages to tie it to the chain first wins the other one will get an orphan hunt, the chain resets with every new animal attached to it, and nobody cares if you are shooting 24/7 or a few mins a year, every shot has a chance to hit a poor animal in the woods.

Your miners are the guns you are pointing to the wood, every bullet is a share, so not only that every gun try to hit a target, it's every bullet, which is why every share has the same chance of hitting a block.

So your 7 S9s are all randomly firing those shares hopping to hit a block, your arrangement of the addresses / workers means nothing to the chances of finding blocks, it just helps you "see them clearly".
 

The bestshare is simply your highest share.

You can't determine the value of your next share - it's impossible. There's nothing you can do, it's totally random.

Once again, you control the number of shares you submit in proportion with your hashpower, and the more shares you submit , greater are your chances of finding a block, but the rest is totally random.