The new G70 does a lot of things well but trunk space and rear passenger volume aren't part of them, especially when compared to key rivals for 2019 like the BMW 3-Series, Infiniti Q50, Audi A4 and Mercedes C-Class.
Its 10.5 cu.ft (298 liters) of trunk space barely measures better than the Cadillac ATS at just 0.2 cu.ft bigger.
Considering it's in a segment with a portion of consumers having few cargo and even passenger volume demands, 10.5 cu.ft isn't exactly discouraging and might be worth the trade off of a sportier rear end design. If you do however need more space, 6:4 rear split-folding seats allow you to carry larger/longer items.
Car and Driver reported they were able to "fit five carry-on bags in the G70's trunk, and another nine with the rear seat folded," and the Globe and Mail "fit three carry-on suitcases and two other bags with room to spare, so family trips are still doable"
"Smart Trunk" allows for hands-free opening and closing with the proximity key, a standard feature across the entire Genesis line up. Standing within detection range behind the trunk few seconds also opens the trunk if your hands are full.
Accessories are limited, Genesis sells a reversible cargo tray (Part Number: G9F12-AC500) that sells for $100-130. Aftermarket brands like WeatherTech have more options like cargo/trunk liners and bumper protectors when loading/unloading.
If you still demand more space, other models like the Mercedes C-Class has 12.6 cu-ft, Audi A4 at 13 cu.ft, Infiniti Q50 at 13.2 cu.ft with the BMW 3-Series leading at 16.9 cu.ft. Your only other option close to the G70 when still shopping Korea is the Stinger at 23.3 cu.ft.