For now I think electrum and others open source wallets are a pretty safe bet, just don't go click in any automatic updates popups.
As I know, automatic updates popups only appear if you download Electrum from an illegal source, not from an official. This happens to me 4 years ago after downloading Electrum from Softonic. So if this happens, one of the ways to clean up your PC is re-install the OS or use a bootable USB like Tail OS.which allows you to increase transaction fees after a transaction is submitted,
Increase transaction on Electrum wallet is more detailed right now, if you don't read and understand how is going you will be confused, and you can't do it before changing the preserve to decrease tab.
I always prefer Bitcoin core wallet with an offline machine(Linux/other os),
Oh God, true, we can safely and can create an offline wallet on that machine, but, when we are going to the transaction, we have to download the full 516 GB+ blockchain data. So, If urgent, you have to import that private key from core wallet to a light wallet like Electrum.