Slow transactions with Web3.py

Question

In my python code I try to send multiples transactions from different address at the same time.

The code build a transaction, sign it and send it, then I print "transaction number n sent" and it continue with the next one. It takes approximately 1 seconde between two print, which means a transaction is sent every 1 seconde, too slow for me.

Is it normal ? Do I need a better computer or internet connexion ? I'm using Infura provider

myContract=w3.eth.contract(address=adresse_contract,abi=abi_contract)
def multi_transactions(gaz_price_gwei):
   nonce = w3.eth.getTransactionCount(adresses[0])
   for i in range (len(adresse)):
       tx = myContract.functions.swap(Token).buildTransaction(
    {
      'from': adresses[i],
      'gas': 200000,
      'gasPrice': w3.toWei(gaz_price_gwei,"gwei"),
      'nonce' : nonce
    } )
       signed_tx = w3.eth.account.sign_transaction(tx, keys[i])
       w3.eth.sendRawTransaction(signed_tx.rawTransaction)
       print("Transaction",i,"sent") 

Adresses and keys are arrays. The swap function in my contract just swap on Uniswap. All transaction have the same nonce