1.3.2 Meaningful Sequence
Stop it already with the CSS flex order and CSS grid column/row placement. Isn't it nice of CSS and browsers to hand you a gun to shoot yourself in the foot with? How else would you learn that the web platform is built for sighted people?
Just make sure your DOM order follows some sort of logical fucking sense. Because screen readers don't give two shits about floats, flexbox, or grid-column.