Trunk comparison: Skoda Karoq vs VW Tiguan Allspace

Key Differences in Cargo Space
With the seats folded down, the VW Tiguan Allspace offers a cargo space that is +13.4 in (22%) longer than the Skoda Karoq. When the first row of seats is upright, the Tiguan is even +14.2 in (47%) longer.
Conversely, the Skoda Karoq has a cargo space that is +11.4 in (62%) longer than the Tiguan when all seats are upright.
Practically, this means: the Tiguan is better suited for very long loads (e.g., long slats, boards, or furniture when seats are folded), while the Karoq offers more usable trunk space for luggage or bags when fully occupied.
Opening, Loading Height, and Interior Depth
The trunk opening of the Skoda Karoq is +7.9 in (28%) higher than that of the Tiguan, and the trunk depth (loading edge to trunk floor) of the Karoq is +5.9 in (1400%) greater. At the same time, the loading edge of the VW Tiguan Allspace is +3.5 in (13%) higher above the road than the Karoq.
Practically, this means: the Karoq offers significantly more vertical space and a lower/easier-to-overcome loading edge — loading heavy or tall items is easier and usability for bulky, tall cargo is better.
The Tiguan requires more lifting effort due to the higher loading edge but offers longer cargo lengths with seats folded down.
Width and Other Points
The narrowest trunk width differs by only +0.4 in (1%) in favor of the Karoq, which is negligible in practice.
The width of the trunk opening is +3.9 in (10%) larger in the Tiguan; this value is exactly at the 10% mark and therefore not a highlighted difference per your guideline but can slightly ease loading wider items.
Conclusion — Usability in Everyday Life
Choose the VW Tiguan Allspace if you frequently transport very long loads and often fold down seats.
Choose the Skoda Karoq if you often travel with full occupancy or frequently load bulky/tall items and value a lower loading edge as well as greater interior height. Width differences are marginal and hardly affect everyday usability.