David wrote:

has anyone tried just fixing a long strip of LEDs to a
ceiling or under a cupboard to provide dispersed lighting?

My dad uses them glued under the shelves on his pottery stall, outside
my porch, I've used a corner diffuser with the LED strip in it ...

https://www.led-lighthouse.co.uk/led-strip-lights/led-strip-aluminium-profile/corner-aluminium-extrusion-for-led-strip