Satisfactory helmet neopixel ear

You can print the original ear cover out of a clear/transparrent LED or use a laser cutter to make a 64mm acrylic ring to shine through. I used black LED acrylic in mine 

Later I will provide schematics and code for microcontroller based LED controller

Later I will create and provide a version for the smaller mask

I used this LED ring: https://www.amazon.com/gp/aw/d/B07437X7SL?psc=1&ref=ppx_pop_mob_b_asin_title
You can use something like this to get it working for now: https://www.amazon.com/Controller-WS2812B-SK6812RGB-Addressable-Portable/dp/B09Y8SWJ77/