The best way to power LEDs
Add a resistor for each LED.

It's better to drive an LED with a constant current, since a small change in voltage will resut in a big change in current. Ideally you want to keep your LED at the 3.8V/30mA point in it's IV-Curve. But if there are some changes you want it to stay close to that.

Your resistor should have the value:
$$
R = \frac{U}{I} = \frac{5V-3.8V}{30 mA} = \frac{1.2V}{30mA} = 40 \Omega
$$
due to resistor tolerance of probably 20% you want to go higher than that, I would try 68 Ohm, if it's important to you that the light is bright choose a lower value, if your main concern is lifetime choose a higher value.

Also keep in mind the Power Dissipation in the Resistors:
$$P =\frac{\Delta U^2}{R} = \frac{1.2V^2}{68 \Omega} = 0,021 W$$

But according to http://www.resistorguide.com/resistor-sizes-and-packages/
a 0603 package can disspate 0.1W so you should be good.

Also if you were to use a voltage divider, it would be hard to make the voltage stay constant, because you are loading it with the LED.

See also:
https://www.digikey.com/en/resources/conversion-calculators/conversion-calculator-led-series-resistor

Also I am sure you can find a few related questions here, that explain different aspects more in detail like this one: Resistor selection for LED