This post was flagged by the community and is temporarily hidden.
Couple of observations,
- Not a fan on diode approach. It will drop current too. And voltage is not guaranteed at <4.2V. If 4.3V appears there, you are in trouble. You can just use one more regulator to step down the 5V to 4.1V. May be L6932 or another LM2596 or LM2576.
- Havent used the transistor level translators. I would recommend the TXS0102 or TXS0104 chips. If the transistors work well for you, you can use it.
- For SIM card, directly connecting them also works, But put decoupling capacitors on all pins and TVS diodes if possible.
Rest all looks ok.