Sortable table headers overlap with each other when scrollable

[anema-eightfold]

Issue:
Sortable table headers have similar z-index even when sticky. If the two sibling headers overlap (ex - in small screens), the later one in hierarchy overlaps with the previous one (ex - in case of sticky headers)

Reproduction:
https://codesandbox.io/p/sandbox/table-sticky-header-sd3r6r?file=%2Fsrc%2FApp.js