What do you mean by order?
Miners assign an index number to each transaction they include in the block and block explorers sort the transactions according to those index numbers.
A transaction having a smaller/bigger index number than another transaction doesn't mean it has been broadcasted earlier/later.
Aren’t the transaction indexes inside a block always ordered sequentially? What I meant by
orderingorder is the order in which the miner includes and executes the transactions in the block. That should be the same as the index order if I am not mistaken. So once a miner assigns an index to a transaction, that becomes the execution order during validation.