Withdrawing from Polymarket is simple, instant, and free.
Note: When withdrawing USDC.e (bridged USDC) is swapped through the Uniswap v3 pool for USDC (native) (the UI enforces less than 10bp difference in output amount). At times, this pool may be exhausted and for extremely large deposits there might not be enough liquidity. If you are having withdraw issues, try breaking your withdraw into smaller amounts or waiting for the pool to be rebalanced. Additionally, you can select to withdraw USDC.e directly which does not require any Uniswap liquidity; just be aware that some exchanges no longer allow USDC.e to be deposited directly.