According to my analysis the best wallet for the security and the lowest transection fees can be Electrum wallet.Here you can easily set your preferred transection fees and it's offering the lowest fees per block for transections.Its my recommendation and I am also using this.
Again There are some Exchange wallets where you need to pay zero fees to make any transaction for some coins.They are Bitstamp exchange and Ftx exchange.But they are not my recommendation.Because exchange wallets are oftenly being hacked.
So For you Electrum Wallet will be the best option Undoubtedly.
I have tried using electrum on android since I have android phone but never tried for ios and I think there is no ios version of electrum yet. Searched many times and never found one that is for iphone devices. As far as I know about electrum is that the lowest transaction fee is 3sat/byte and it's within 25 blocks.