As you found out, the CSS multi-column module is not very well specified, and browser support is severly lacking in both features and performance. Unfortunatel

As you found out, the CSS multi-column module is not very well specified, and browser support is severly lacking in both features and performance. Unfortunately... no, there's no better css only alternative. Grids are not supposed to address that use case. For now you are much better off looking at "masonry" javascript implementations, because they actually work and exhibit better performance than css columns.