The history of app stores is pretty clear on this — the primary ways to get non-negligible exposure is to get promoted/featured (literally “picked as a winner”), or somehow trigger a viral word of mouth event. One can pay to advertise an app, but that isn’t likely to support long-term product development (expense vs revenue).
Nonetheless, there are success stories so if you believe in what you’re building keep at it and keep talking to folks about it.