After trying iNav 5.0 and Optical Flow several days, I meet several problems.

1. Motor current is too high, and the MAX Current shows 26A(it may be incorrect).
2. Optical flow can not work with GPS on PosHold and AltHold mode.
3. Default PID and RPM filter is not good as Betaflight.

Therefore, I decide to remove optical flow and use betaflight 4.3.
Because of raining days, I test hover flight indoor and get around 11A max current and average 9A(including 1A 25mW HDZERO and 0.5A GPS and ELRS EP1). (It should fly around 20-30 mins for 2S 3500mah)
The throttle is around 56-70%(8.2V-6V)(8.5A-10A) and bad, so cannot do freestyle action.
I will try to change props to decrease a little throttle.

2022 6.16 Update:
The 3500 mah 18650 can work 4.2V to 2.5V.
But when battery approch 6V(single 3V), throttle increases above 70% and flight attitude is not stable.
I think it should be F7 Fc only support 2S-6S. May try 1S-3S FC or change to 3S 18650.
2022 6.16 Update:
12V booster is broken after connecting 3S battery, so remove it.
Change to use 3S 18650: Total weight around 250g / throttle 41% (12V / AVG 7.5A-8A)
I'm satisfied with this settings.

2022 6.17 Update:
Hover Test

2022 6.29 Update:
Move 1 battery tray to bottom and add GPS