blockchain – my questions concern the exploitation and the transaction

after 10 min, all will choose a transaction in their transaction pool and start creating a block,

It does not work that way: all miners try to create a non-stop valid block (called extraction). On average, a valid block is found every 10 minutes.

When posting a transaction, most miners will add it to their block template (if there is enough space left). On the other hand, minors are allowed to choose their transactions, or leave the block empty, or fill the block with their unnecessary free transactions. Thus, they can have different transactions in different orders.

[Question 2]

The blocks will compete: the next block will choose one and it will be the longest and most valid channel. The other block will be orphan, or not accepted by the network.