Never mind - I managed to get it to work 15 minutes after posting this
For anyone who ever has the same issue, here’s what I did:
-
I used inpier’s configurable device handler initially to set the min and max brightness for the dimmer (parameters 12 and 13) to 10 and 20 respectively.
-
After saving that configuration to the device and confirming it worked, I switched back to Smartthings’ Fibaro dimmer device handler.
And boom! Works perfectly. I think the issue was that my LED lights have a very narrow dimming range, i.e. 10-20 compared to what the Fibaro dimmer can do.