Greetings! I'm a new dev myself, take my advise with a grain of salt but for indie devs, esp for making/releasing your first set of games, you don't need set up costs.
You just need to A) Make a good game, B) Have places outside of itch to promote it, C) Have a good bio to gather people in, D) Have a good trailer and thumbnails to capture visitors passing by.
Only startup costs that apply to developers if you are starting your own game studio or trying to publish your game through someone elses game studio.