Weirdly similar kanji

英 and 栄, 営 are unrelated as far as phonetic components go. 英 comes from 央 (えい・おう・よう), and 栄, 営 come from 𤇾 (えい・ぎょう).
There are also other kanji with same components which have different readings (蛍, 労, and a billion kanji with the component 艹 which comes from 艸).
In short, if you remember that “sparks” = えい, you’re going to be very confused when you encounter all the exceptions to that rule. If you’re using WK I strongly recommend this extension.