The right marketing channel is the one that allows you to scale cost-effectively.
Start with the growth you need in your next phase, how many new customers it will take to achieve it, and how much you can afford to spend acquiring each one.
Then identify where those customers discover and evaluate your product. Test the most promising channels with a small exploratory budget. Use what you learn to rank them by their ability to support your growth within budget, and invest in order of priority.
Give each channel a clear purpose, measure its contribution, and adjust the investment as you learn.