Web3 Startup, Infrastructure or dApps?

Hi friends, for any startups, founders, advisors, developers, I got 2 questions, please state your experiences too!:

1) There are many rollups layer 2 in development and coming out, if you are in my position of wanting to innovate, should we focus on building more infrastructures or on decentralized applications built on top of these newly launched layers 2?

2) With the rapid advancement of technology, how do you stick with what you want to build? I'm sure that you have multiple ideas going on in your mind, how do you execute and stay convicted to one without thinking the about the others?