We will be happily building out features while your engineering team wastes time solving for scaling problems that you will never have because you don't have features your customers want.
Choosing database A instead of database B doesn't mean you're suddenly "solving for scaling problems". It just means you're better prepared to one day solve scaling problems, should your product take off.
Every choice has trade offs. And database sharding should be very low in your priorities when starting a project because YAGNI. In particular, I will actively laugh at anyone not choosing Postgres « because it does not scale enough » when starting a project. Postgres Pros overwhelm massively this imaginary potential Con.
We will be happily building out features while your engineering team wastes time solving for scaling problems that you will never have because you don't have features your customers want.