And your 8.3 V VF is unrealistic. The circuit will only start regulating correctly at around 1.8...2.0 V drop.
NOPE, I have real circuit with real electrons and when powered from 12.3Vbat LEDs had ~8.2Vf@50mA, so very close to shown value in my simulation
Now, I've added 3rd BC547C transistor to drive second 22R from MPU (Attiny85) powered by... 3.05Vcc made of... yes.... 3V9 Zener diode (BZX85C3V9) and ~1.5k resistors (1k+470) protected by 1N4148 diode
So far so good, MPU pin 3V drives via 10k resistor BC547C resistor R22 to ground at voltage level ~0.13Vt, so in real circuit now when driven from MPU pins, now I have LEDs current:
0.61Vr/22R ~0.028mA
0.48Vr/22R ~0.022mA (~0.13Vt ground transistor)
so total LEDs limited current is... 50mA and this is not a simulation but real circuit shown below
Now it is time to write some MPU code running at 8MHz since it is powered from ~3Vcc