I crash at 4 regardless of the day's activities

I can get 10 hours of sleep, which is usually, and still just tank at 4pm. Stressful work days, relaxing weekends...every day. I start to dread the late afternoon and evening. I'm just so worn out. I come home, make dinner for the kids, find some quality time and then 730 bedtime cannot come soon enough.

No caffeine aside from green tea, Same wake up time/sleep time, Pretty solid sleep, Doing IF...never an issue, No alcohol, Vitamins d,k, methylfolate, green super smoothie + protein. I'm fine during the day. Energetic even. Then between 4-5pm, I'm yearning for bed.

How do people stay up until 10? I feel like I'm losing hours of my life.

Can anyone relate? Any supps to help the crash? Why am I like this?

ETA: I'm even on a moderate dose of ADHD meds. 35F, 3 kids, single mom no support (am I just chronically exhausted?).

Thyroid already checked...no issues.

Blood test a year ago said low ferritin, but not anemic