I'm using the reversible trunk liner that came with my Santa Fe (from Hyundai), using the rugged side (non-carpeted). The SmartLiner set I bought for the 2021 was just front and second row. The Hyundai trunk liner is relatively flexible and still gives access to the under-storage. It doesn't provide a deep bucket like I had in my 2004, but good enough for now. I may get their 2019-2021 trunk mat eventually if reviews suggest it really is compatible with the 2021, but I'd expect it to make the under storage more difficult.