Case 1.
When sending form multiple T inputs (coin control) to S, usually fee is under calculated and wallet will notify about such "insufficient balance", to correct, re-open coin control window and copy new "after fee value" and works

Case 2.
When sending all multiple T inputs to S, fee over-calculated, send no problem but dust goes back to change address.

Fix as a feature, like in case of other crypts CRW, SYS add an option to send "subtract fee from amount".
For example you have 1.53427648 and try to send all 1.53427648, you need to calc the fee via coin control window and send less that fee (that could be calculate wrong see Case 1,2)
In case of "subtract fee from amount" checkbox, you enter what you want to send and agree destination will receive that mins fee calculated, so you would know what will arrive at destination only via confirmation window.

Visual from SYS

And confirmation window