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.
No, we have seen a user that downloaded from the official Electrum website years ago but was still scammed by the pop-up Electrum wallet notification. I think a strategy used by online theft to steal from BTC and download from the Electrum official website is not enough either if the wallet is not verified.
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.
Creating an offline wallet using Electrum is better.