Question about Ugreen NASync DH2300 +HDMI Cable Bundle

According to my research and taking into account the manufacturer's specifications, WD Red Plus HDDs are recommended. You can select different storage capacities in the following link. Ideally, both should have the same storage capacity:
- https://www.digitec.ch/de/s1/product/wd-red-plus-4-tb-35-festplatte-22886688