Yes, this is correct, but the block of transactions that every node verifies was proposed and added to the chain by a miner running a mining node.

And currently, over 75% of the blocks being added to the chain (proposed) are constructed by 4 nodes (pools, companies).

The miner will choose ~ 2500 out of the current > 200,000 transactions in the mempool to construct a valid block. The other 198,000 remain in the mempool.

There is the thought that miners will simply construct a block which generates the highest fees, but this has already been proven wrong.