Get 3 blocks to NOT stack vertically on mobile

Two options; given that you don't have these with any hover effects or links, you could simply do what you did with the growth numbers below, and have a single static image. Or, you're on Squarespace 7.1 and you could enable Fluid Engine which allows you to directly design your layout on mobile in a way that you can't with the classic editor. (this should be done with caution and after learning about the differences, check out this guide: https://support.squarespace.com/hc/en-us/articles/6421525446541-Fluid-Engine-Squarespace-s-latest-content-editing-experience)