I know LED bulbs don’t like old-school dimmers, but I haven’t really looked into ones made for LED bulbs; I’m assuming they work different and aren’t just a variable resistor on a dial.
As I understand it. LEDs work on PWM. The controllers should regulate it as needed.
So it’s changed from 120 to whatever internal DC current is needed and that’s cycled.
When you use a dimmer you’re lowering/raising that 120v which is messing with the bulbs AC/DC converter which is designed to take 120 and output the applicable DC current for whatever LEDs it has on the circuit.
It definitely won’t adjust the PWM rate or brightness except in some extreme range and I’d personally avoid it unless you have some bulb that says it’s fine (e.g. doing something clever to adjust the DC based on the AC input)