stove
烓 centers on a stove: a device for cooking or heating, typically involving fire.
烓 combines 火 (fire) with 圭, which likely contributes the sound. The exact historical development is uncertain, but the structure suggests a phono-semantic compound related to fire or a stove.
The left side is fire 火, and the right side 圭 looks like stacked earth or a piled-up structure. Picture a stove made of piled earth with a fire burning inside: 烓 is a stove.
For エイ, imagine an 'A'-shaped stove: the letter 'A' sounds like エイ, and the stove's shape resembles an 'A' with fire underneath.