Well, like you said, let's assume a magic happens today and I became a developer which is going to last only for a few hours or minutes, then I would first of, create a decentralization blockchain platform that can allow every Bitcoiner from every part of the world to freely and easily buy and sell Bitcoin without going through KYC procedures. Secondly, I will remove Bitcoin from every centralized exchange if that's possible to do, then allow btc to be traded only on the DEX or other DEX.
Creating a new project in cryptocurrency is very easy and anyone can do it, but making the project you are developing have lots of fans is not as easy as you currently imagine. Developers need quite a lot of capital which is used to carry out campaigns or advertising costs which are used to promote the projects being developed.