Leaving such huge amount on hot wallet is not a good idea, hardware wallet should be used for huge amount like that, I will even advice anyone having more than $500 worth of bitcoin to use hardware wallet, or if the person know how to handle other offline wallet, they can be recommended also.
Hot wallets are not secure like offline wallets, but web wallet like blockchain.com are most vulnerable type of hot wallet because it is a web wallet, web wallets are not even recommended at all. There are many complains of coin lost on blockchain.com wallet, you need to transfer you fund immediately.
Download electrum wallet immediately
[GUIDE] How to Safely Download and Verify Electrum [Guide]Create a new electrum wallet and transfer the remaining funds there.
You will need to buy hardware wallet, or make use of offline wallet. I will recommend Trezor (open source) or Ledger Nano (close source). If you buy Trezor, make sure you use passphrase, and do proper backup because if the seed phrase and passphrase are lost, you will lose your funds. If you do not use passphrase, be careful for thieves not to steal your Trezor because they can be able to know your seed phrase, but the passphrase in this case will help you to generate another keys and addresses entirely, this will make it the type of attack impossible.
Make sure you buy from legit reseller, but buying directly from the official hardware company is recommended. You will have to transfer the fund from electrum to hardware wallet. And make sure you protect your wallet.
The transactions with the above txid have been confirmed already. It can be due to hackers that are able to use malware to steal from your devices or someone get access to your phone to steal it. Make sure you are using password or pin to access your wallet.