though Electrum on mobile lacks some very good features like coin control, customizing fees, signing a message, etc.
You are wrong, I don't know where you get this statement but coin control and fee customization is available on Electrum for a very long time.
Coin control android :
https://github.com/spesmilo/electrum/issues/5661Also, it seems that now sign-in message is also available now but I am not aware of it or can't find it in my updated android too so probably it's still not updated on play store but the sign-in feature on the electrum adroind has been implemented recently.
Github:
add sign message feature to android qml
In my opinion, the weakness of the bluewallet wallet is that it is not a wallet for storing large amounts of assets in the long term.
Correct, but the same is true for Electrum as a hot wallet or any other hot wallet for that matter.
Both these apps can even be used as cold storage too if we install them on an air-gapped device but it is definitely for advanced user only.