shine
燿 centers on emitting light: shining, glowing, or radiating brightness.
燿 combines 火 (fire) with 翟, which likely contributes the sound and originally depicted a type of pheasant with bright plumage, reinforcing the idea of shining or brilliance.
Fire 火 on the left and a bright-plumed bird 翟 on the right: imagine a pheasant's feathers glowing like flames, making the whole character shine.
For ヨウ, picture a glowing yo-yo spinning in the dark, its light shining brightly: yo-yo -> ヨウ, and the fire 火 makes it shine.