Hi Scott,

you have to use bootstrap 5 class name. I created that tip months ago >> https://www.joomshaper.com/documentation/helix-framework/customization-tips#how-to-make-the-bottom-menu-vertical-instead-of-horizontal

Later, sometimes extra CSS may be needed to add space between menu items.

Example (for real footer, not bottom):

#sp-footer .sp-module ul {list-style: none;}
#sp-footer .sp-module ul li {margin-right: 10px;}

Example (for bottom):

#sp-bottom .sp-module ul {list-style: none;}
#sp-bottom .sp-module ul li {margin-right: 10px;}

simple code and fully described in Helix documentation :)