I had a spare Spyda LED light fitting for a VentAir Spyda overhead fan, which I have put to use as a flat field source, coupled to a spare laptop power supply. The unit runs from about 18-24V, at 20W (dimmable in 4 steps with an appropriate controller, which I havent used). The light is slightly domed, which helps it sit on the telescope, as pictured, with an illuminated diameter of 165mm. The illumination is pretty uniform, and can be improved with the "standard white t shirt" if required. (The photo is taken with the light off). They are available at lighting stores or (in lockdown ...) over the web, for around $60-$80.
Ed