Bootstrap Utility Display Property

It doesn't seem as if display properties work with the Pearl Theme, https://getbootstrap.com/docs/5.0/utilities/display/

I'm wondering if there are any utilities in the css/scss that I'm missing, such that I could display certain things on mobile and others on desktop.  

I know I could add in my own custom scss, but it seems as if this might already be built in, and I'd appreciate it if anyone could point me in the right direction.

Thanks!