Hi,
Let me address your questions one by one.
1. Points multiplied by quantity
This is the default behavior. When a customer buys 3 pieces of a product that gives 7 points, the points plugin will give 3 x 7 = 21 points. You don't need to configure anything special for that. If you're not seeing this behavior, make sure the points plugin's "Give points when using some" setting is set to "Give on full price" (which it is in your screenshot).
2. Paying with points (partial or full)
In your "Pay with Points" payment method configuration, you have "Partial payment" set to "No" and "Minimum (percent)" set to 100%. This means the customer must pay the full amount in points or not at all. To allow partial payment (points + money), set "Partial payment" to "Yes" and lower the minimum percentage. For example, setting the minimum to 0% would allow the customer to use whatever points they have and pay the rest with another payment method.
However, there is an important thing to understand: the "Pay with Points" payment method works as a standalone payment method. When partial payment is enabled, the remaining amount after deducting the points value will need to be paid with a second payment method during checkout. The customer would first select "Pay with Points", which deducts what it can, and then a second payment step is presented for the remainder.
3. Exchange rate configuration
Looking at your screenshots, there is an inconsistency in your exchange rates. In the "Pay with Points" payment method, you have 1 point = 0.25 EUR. But in the points plugin, you have 1 EUR = 1 point. This means the customer earns 1 point per EUR spent but each point is only worth 0.25 EUR when redeeming. Make sure this is intentional. If you want points to have a 1:1 value with EUR, set both to the same rate.
Also, you have the product custom field "userpoints" set to 7 for a product priced at 39 EUR. If you're using the custom field to define a fixed point cost for products, this means the product costs 7 points (= 1.75 EUR at your current 0.25 rate). If you want 7 points to cover the full 39 EUR, you would need to set the rate to approximately 1 point = 5.57 EUR. Alternatively, if you want each product to define its own point price independently from the EUR exchange rate, you can use the "Custom field for price in points" setting, which overrides the exchange rate calculation for that product.
4. Coupon workflow issue
The issue you described with the coupon being generated and the checkout going back a step is related to the "Virtual coupon" setting, which is set to "No" in your configuration. When it's set to "No", the system generates a real coupon code that the customer needs to apply manually, which causes the confusing workflow you described. If you set "Virtual coupon" to "Yes", the point discount will be applied automatically without generating a visible coupon, and the checkout flow will be smoother.
Regarding the points disappearing when a coupon is deleted: if "Return points on cancel" is set to "Yes" (which it is), the points should be returned when the order is cancelled. But if the customer just deletes the coupon without cancelling the order, the points may not be returned. This is expected because the coupon deletion is not the same as an order cancellation.