Because of the way the Native Bridge operates, users are required to wait when moving assets out of a Rollup onto The Settlement Chain (ie. Ethereum Mainnet, Arbitrum One etc...). This period of time is called the Challenge Period and serves to help secure the assets stored on the Rollup.

You can find more information about the Challenge Period here.

If you need a faster bridge transaction you might want to use an alternative route such as Hyperlane or Across. They provide faster bridging services (but some charge a small extra fee). Please note that their token selection may be more limited.