I am trying to make a swap transaction on Raydium using Python. I always preparing the transaction and necessary instructions for the swap in advance:

print("Add Instructions To Transaction...")
swap_tx = Transaction()
signers = [payer]
swap_tx.add(modifyComputeUnits)
swap_tx.add(addPriorityFee)
swap_tx.fee_payer = payer.pubkey()
if swap_token_account_Instructions != None:
    swap_tx.add(swap_token_account_Instructions)
swap_tx.add(instructions_swap)

Those instructions are not the issue, they work fine. I run needed code for sending the transaction in a loop and all I am changing is the recent_blockhash of the transaction. After that, I try to simulate the transaction to make sure it does not throw any errors. If there are no errors, I send the transaction. I am using max_retries=0 to customarily resend the transaction. I am attaching the relevant code.

    while txnBool:
        """Send transaction"""
        try:
            blockhash_resp = solana_client.get_latest_blockhash(Confirmed)
            swap_tx.recent_blockhash = blockhash_resp.value.blockhash
            last_value = blockhash_resp.value.last_valid_block_height
            print("5. Execute transaction...")
            txn = solana_client.simulate_transaction(swap_tx, commitment=Processed)
            if txn.value.err == None:
                send_time = datetime.datetime.utcnow()
                print(send_time)
                blockheight = solana_client.get_block_height(commitment=Confirmed).value
                while blockheight < last_value:
                    print("Trying to send")
                    new_txn = solana_client.send_transaction(swap_tx, *signers, opts=TxOpts(skip_preflight=True,
                                                                                            max_retries=0),
                                                             recent_blockhash=blockhash_resp.value.blockhash)
                    txid_sig = new_txn.value
                    try:
                        status = solana_client.get_signature_statuses([txid_sig])
                        status = json.loads(status.to_json())
                        if status["result"]["value"][0] != None:
                            print(status)
                            success_time = datetime.datetime.utcnow()
                            print(success_time)
                            print("Transaction Success", new_txn.value)
                            print(f"https://solscan.io/tx/{new_txn.value}")
                            txnBool = False
                            break
                        else:
                            blockheight = solana_client.get_block_height(commitment=Confirmed).value
                    except Exception as e:
                        print(e)
                pass
            else:
                print(txn.value)
        except Exception as e:
            print("Exception, Retrying")
            print(e)

The problem is that there can be a difference of up to 15-20 seconds between the send_time and success_time values.

Also, in the transaction, I am already using a priority fee, and there should be no issues with the rpc node as well. I see on solscan that people are able to send transactions quite quickly, literally tens of transactions per second, even though they use a priority fee much lower than mine, but their transactions reach the target at the right time, while mine do not. Please advise me on what I am doing wrong, perhaps I am using the wrong methods.