The reflector of the flashlight is built so light coming from a very small source (like the filament of an incandescent bulb) is directed forward in a focused beam.

I agree, but I also think that using a modern LED with a single source of forward-facing light is fine. However the emitter would need to be properly positioned in the light.

Here’s a very similar host (from one of the best low-cost flashlight makers) showing a properly aligned LED and reflector:

Product link: https://www.aliexpress.us/item/3256801849471618.html

I found a few references to this exact model on candlepowerforums.com which I believe has more folks who own(ed) incandescent lights. Not that has been such a long time, but LED technology advanced very quickly. Not sure if that will help your search.

There’s also a few people over on !flashlight@lemmy.world !