On the other hand, if you comply with EU data policies, your customers might choose your app over another app that doesn’t
(especially european users, and businesses)
Of course. Such are the decisions and tradeoffs that any young startup needs to make. That's why I said that they could take it or leave it.
Don't make any plans to have a physical EU footprint and you can care less what the EU thinks of your internal policies. EU customers can take it or leave it. Their choice. It's not a warm stance to take, but you've probably got a dozen other balls in the air that you're juggling. EU data compliance probably isn't one your worried about as a small startup.