Trunk comparison: BMW iX1 vs VW Golf Wagon

Key Differences (Highlighted)
The VW Golf Wagon offers a cargo space that is +9.8 in (15%) longer with the rear seats folded down than the BMW iX1, and with the first row of seats upright, the trunk is +7.5 in (21%) longer.
The depth from the loading edge to the trunk floor is +3.5 in (≈+450%) greater in the Golf. Conversely, the loading edge of the BMW iX1 is +4.3 in (18%) higher above the ground than that of the Golf Wagon.
Impact on Usability
Due to the significantly greater cargo length (with seats folded and upright), the Golf Wagon is better suited for long items (e.g., lumber, skis, or long boxes) and for loads that need to extend over the rear seats.
The considerably greater depth between the loading edge and trunk floor in the Golf also creates more vertical space in the cargo area—this makes stacking and retrieving lower items easier and increases the usable interior height behind the loading edge.
The higher loading edge of the BMW iX1 means more lifting effort when loading and unloading heavy items; for regularly heavy or bulky cargo, the BMW is less comfortable.
However, a higher loading edge can have advantages in some cases (e.g., preventing sliding on inclines), but here it is a comfort disadvantage when lifting.
Other dimensions such as the height of the trunk opening (+2.4 in / 8% in favor of the Golf) and widths (at the narrowest point +0.4 in for the Golf; opening width +3.5 in in favor of the BMW) are below the 10% threshold and are minor in practice—they hardly change the fundamental usability.
Summary
For users who frequently transport long, deep, or difficult-to-load items, the VW Golf Wagon is clearly more suitable in practice. The BMW iX1 has a higher loading edge, which makes loading more difficult; advantages of the iX1 over the Golf are only minor in the dimensions given here.