You could simply use a LED DRIVER with ability to control the brightness through a PWM pin or by setting a resistor.
Note that if the led is at quite a long distance away from the control box, you should account for the wire resistance as well ( the circuit would most likely use a low value resistor like 0.1 ohm for example to measure the current ... so if you use a few meters of AWG18 wires with 21 mOhm per meter of resistance, that can affect the 0.1 ohm value) .
If you want to be really accurate you could have the current sense resistor near the led and then you could use a couple of thinner wires or just one thinner wire to bring the actual voltage measured to the control IC.
Check out for example Richtek RT8463GQW :
https://www.digikey.com/product-detail/en/richtek-usa-inc/RT8463GQW/RT8463GQWCT-ND/6205469It can work with up to 50v and can operate in either buck mode (step-down) or boost mode (step-up) so for example you could design your circuit to either use a 12v..24v power supply and boost the voltage to ~34v (go as high as needed to get 1.5A through the led) , or you could for example use a 48v power supply and take that down to the voltage the led requires.
The current is controlled through a current sense resistor, a 100mV drop sets the maximum current allowed through the leds.
See page 6 of the datasheet for example circuits using analogue ( 0.2v to 1.2v range for 0..100% brightness) or pwm dimming
Another chip worth looking up (but more expensive and boost only) would be LT3952 :
https://www.digikey.com/product-detail/en/linear-technology/LT3952EFE-PBF/LT3952EFE-PBF-ND/5253630