Reddit mentions of Westek 6079BC 500W Full Range Replacement Dimmer, Black

Do you mean equivalent to a 5-10W incandescent bulb?

If you scroll down that list of Home Depot search results, there are a number of 25W LED bulbs which would be significantly dimmer than the 40W ones.

Another approach might be to use a dimmer together with a dimmable LED bulb. The Philips Warm Glow LED bulbs work really well for this (I have those all over my house on dimmers).

(1) This is a handy dimmer that can be easily hidden inside lamps and fixtures (just make sure to verify your setup with a professional electrician, etc. etc.):

https://www.amazon.ca/Westek-6079BC-Range-Replacement-Dimmer/dp/B000FPDHKA/

(2) If that doesn't work, then this style pluggable dimmers which let you control one or more lighting fixtures (just make sure you don't exceed the rated wattage):

https://www.homedepot.ca/en/home/p.credenza-300w-plug-in-lamp-dimmer-in-brown-with-night-light.1000840047.html

(3) Lutron Diva dimmers look like normal wall switches, except they have a subtle dimmer control on the side. Dimmable LED bulbs are compatible with these and they work really well (also have a number of these in my house).

https://www.homedepot.ca/en/home/p.lutron-diva-600-watt-single-pole-dimmer-with-wall-plate-white.1000109549.html