I think the Chinese brands have really hit Samsung hard. Unfortunately Samsung doesn't help itself because it's products are consistently higher than the competition in the same segment. For the same price a Chinese phone will offer better design and features.
Samsung should cull the super cheap products, and focus on the budget segment between €300 - €500 and offer phones with snapdragon chipsets, modern design, good cameras, headphone jack, SD card slot, waterproofing, a charger and case in the box and good screens with at just 90hz refresh rate.
Price them the same as the Chinese competitors and outsell them. This will help with the profits.