Mycrypto or MEW is basically the same, if you want to securely use both, make offline wallet by using their given source code in the github, it's way better than accessing it online so that you won't get phished into someone else's website giving away your private key.
Otherwise if you want a real security measure just buy hardware wallet instead and if you want an absolute security over your asset especially if you want to hold it for a long time, buy a mini pc and install wallet inside it, import privkey and never connect it to internet until you will spend the asset inside.
Sound advise, just use metamask for added security when sending ETH and other token. Also, do not open links that contains suspicious script or urls. Phishing is rampant nowadays. You can also add the EtheredressLookup extensions if you are using chrome.