Nope. You can raise just the front with no issues.
I recommend keeping the front about 3/4”-1” lower than the rear, when you measure the heights at the wheel well openings. Otherwise they tend to look like they are sagging in the back.
Also a recommendation…jack the front of the truck up with a floor jack to what you think is your desired height increase. Then step back and walk around it looking from different angles. That will help you narrow down what actual height increase you are desiring in the end, before you start tearing stuff apart.
A truly leveled truck (by measurements from the fenders) definitely looks low in the back on a Ram.