extravagant
奓 centers on excess and lavishness: being extravagant, wasteful, or overly generous in spending or display.
奓 combines 大 (big) and 多 (many), suggesting something large and abundant, which fits the extravagant meaning. The exact historical development is uncertain.
Big (大) and many (多) together: imagine a huge pile of many expensive things, an extravagant display.
For タ, picture an extravagant party with a tall tower of many treats: tall -> タ, and the big (大) many (多) things make it extravagant.