they have an example using d-grid for buttons

https://getbootstrap.com/docs/5.0/components/buttons/#block-buttons

with gap but…. grid has columns too

where are those utility classes?

tailwindcss has an example:
https://tailwindcss.com/docs/grid-template-columns

>Solution :

Bootstrap CSS Grid will be implemented in Bootstrap only as from version v5.1.0.

Grid col classes infos here at that paragraph of the above docs
page:

Replace .col-* classes with .g-col-* classes. This is because our CSS Grid columns use the grid-column property instead of width.