When a coin graduates, its liquidity moves into a DEX pool and is locked for good. The creator cannot withdraw that liquidity. On BNB Chain and Robinhood Chain the pool is on Uniswap V4. On Solana it is on Meteora.
That does not remove all risk. A creator can still sell the tokens they hold, and a coin can lose most of its value. The creator reserve is 2% of supply (20M tokens). On Solana it is released at graduation. On BNB Chain and Robinhood Chain it is released no earlier than 1 hour after graduation, and only while the price is at or above the graduation price.