If you need to dim/brighten at different rates (faster/slower), you might not even want to get a light with a ramping UI. You’d have to (typically) brighten before dimming, you might get the top-/bottom-of-range blink, etc. Also, some have horrible profiles, zipping from lowest to what seems like full power in a second or two, then slooooowly getting brighter to its true 100% setting. (Ie, it’s not “visually linear”.)
You can get a light with a slider or ring that directly controls brightness, like the DV-S9.
Want a hacque? Whatever bright light you end up using, use diffusing film on the front glass, to blend the hotspot and spill and remove any artifacts from the beam. Maybe even 2/more layers, as you only lose like 2% light per layer.
Mount the light somewhere as needed, and slide a small sheet of metal in front of the lens to varying degrees to get as much/little light as you need, like an iris or shutter. That, you’d have to figure out the best way to do it.
Easier hacque? Workshop lamp (plain lightbulb in a brushed metal “bowl” to reflect light) and a plain ol’ light dimmer.
Like this, but the older style: