In my opinion, there is no best because all wallets have their own advantages and disadvantages, and it all depends on your needs to choose which wallet is suitable and suits your needs.
I don't agree with this statement, what is the disadvantage of using a open source, self custodial, well-reviewed wallet on an airgapped device. There are wallets that are unsafe and shouldn't be used, I.E. Coinomi. You shouldn't say all wallets have their pros and cons, like people should just select whichever one they think suits their needs, meanwhile there are wallets that people should not touch if they don't want to lose their funds.
And what are the best ways for me to keep my cryptocurrencies safe?
You have already received good recommendations on the wallet to use. The best way to keep your coins safe once you are using a good wallet, is to ensure you have a good opsec and learn how to add extra layers of security, such as extending your seed phrase with a passphrase or creating a multisig wallet.