How to align buttons in columns

This is not currently possible using only the UI, unfortunately. (We’ve also wanted to do this forever!)
You can do it with custom CSS, such as this: https://www.geeksforgeeks.org/how-to-position-a-div-at-the-bottom-of-its-container-using-css/

Another thought, can you use a spacer block after some of the text? Or have the buttons in another set of columns underneath the first?

Or have the buttons in another set of columns underneath the first

This has potential here, but be very careful with smaller screens. If your columns collapse on mobile, the buttons will become all disjointed form the rest of the columns. (And if you don’t collapse on mobile, it’s going to be very difficult to read.)

I’d highly recommend the custom CSS option (until this becomes a core feature)