It's not easy to open a channel with all the available balance today.
You need to first try with all the balance, get the error message and then calculate the fee that was required and subtract that from the balance.
A solution to this could be a toggle named "use all balance" that make the calculation for the user.
The benefit with spending all is not getting any change output and end up with a tiny UTXO that will add additional cost to spend later.
It's not easy to open a channel with all the available balance today. You need to first try with all the balance, get the error message and then calculate the fee that was required and subtract that from the balance.
A solution to this could be a toggle named "use all balance" that make the calculation for the user.
The benefit with spending all is not getting any change output and end up with a tiny UTXO that will add additional cost to spend later.