An effective solution for this problem recommended by a large community of store owners is the Magento 2 Reward Point extension with powerful functionalities including:
- Reward points to shoppers for orders, review submissions, registration, and other actions
- Allow shoppers to use points to pay for orders
- Refund shoppers by points instead of paying back money
- Send emails to notify shoppers about the expiry date to motivate them to use point rewards.


I've tried Magento rewards points by BSS Commerce. Installing was supported by the company with a free lifetime update. They also offer one-year support for free.
I also combined reward points extensions with others such as Magento 2 one-page checkout extension, Magento 2 quick order, and Magento 2 quote to boost sales more effectively.
You should try it and wait for better sales.