What is the correct way to drop voltage in circuit

[ashutamar]

Hi Team i designed the schematic shown below for my automotive GPS Tracker

Screenshot 2024-05-27 1500131355×883 62.2 KB

Here i used diodes for droping the voltage

1. main regulator D17 used for 5 to 3.8v approx.
2. auto bat circuit D7 used as 4 - 3.8v approx.

so I'm Just thinking that is it the correct way to do this for long run
or any better way to do this

please give your suggestions and recommendations.

Thanks in Advance