Arbitrum and Optimism are 2 projects that I want to bet on, they all have the same potential. I don't think layer2 will fail, it solves a lot of problems for layer1 and ethereum's upgrade doesn't affect layer2 development at all. Alternatively, you can also consider investing in Polygon, it is sidechain rather than pure layer2 but very promising and solves similar problems as Arbitrum and Optimism.