Why is Electrum better than Exodus? Both wallets encrypt private keys and keep them on your device. Maybe I'm wrong, but I think that most of non-custodial wallets are the same.
Electrum for me is much better than Exodus because it is a fully open-source and multi-signature wallet.
Probably you need to read this comparison between two of them,
Exodus vs. Electrum: The Full Comparison.
Exodus and Coinomi wallet are almost the same for me, but when it comes of most security features, Electrum might a good choice and it's focus only for Bitcoin storing.