Growth from the customers you already have: reviews, referrals and win-back.
The cheapest growth in most businesses: customers who come back, say so in public and bring their friends. It is usually the least managed, because nobody owns it.
I find where the asks belong in your sales and service. A specialist sets up the reviews, referrals and retention programmes and runs them.
A 30-minute call first. If it fits, two calls in one week and a written growth plan you keep.