What are the risks/downsides of using L2 solutions?

I'm thinking about moving my assets over to arbitrum or optimism. I read some really good things about them such as reduced gas fees or faster transactions. However, I could not find any downsides to them. Are there any risks when using L2 solutions? Can I lose my coins if they get hacked? What things should I consider before migrating to them?

EDIT: Can anyone recommend good tutorials about migration? I'm getting some dms telling me to do some stuff before moving my assets but I honestly don't know if they are scammers