I want to horizontally align items in multiple parallel columns under one column block

There is a way to do this without writing CSS but it has its limitations. The styling will have to be tailored to the content and care taken to keep it working if the content changes. You’ll have to be using a version of WP >= 6.2 and nest the title, description and button within a Stack group variation. Then you can assign matching heights to every title and description. Setting the heights is a balancing act of trying to make it work at all screen sizes (to account for heights necessarily increasing in narrower screens with more text wrapping) versus how you’d like it to look at any certain screen size.

Here’s an example you can paste into the block editor.