A betaflight F4 flight controller can draw 1.5A max @ 5V
If your main load is 10A that's only 15% mismatched loads.
If so, the problem is those cells will deplete 15% faster.
The only thing that kills a battery pack faster than excess load current is cell imbalance under heavy loads. The reason is even though they may be 0.1% matched the best case when new, the weaker cell drains first and this accelerates the cell capacity faster and faster ( capacity runaway effect) so when it becomes 10% it will increase its ESR at the same time resulting in more cell heat and faster ageing rate and thus faster cell capacity mismatch and lower cell voltage.
So if it is a low percentage DoD is not as critical but as imbalance degrades DoD and CV level of charge 4.2 vs 4.1 or 4.0 becomes more critical to get life charge cycle rating. Of course its only money and life expectancy of charge cycles. Why? because individual cell under voltage duration and cell overvoltage duration accelerates "cell death"
Cell balancers are usually passive and limited to some power level which is a small percentage of total Watt capacity and normally limited to CC range for charging not CV. But if you have fancy "flying-inductor SMPS bridge cell-balancer" ( my name), no worries. Patented but expensive.
My recommendation
Use full cell voltage and a 5V buck converter or whatever is needed for the flight controller.