Hi @bendl,
Thank you for reaching out and sorry for the frustration with the header and footer builder.
On mobile, the columns are automatically stacked and you can share the same 3 columns but style each column differently for desktop and mobile as shown in this screen recording. Could you please verify if these are the steps that you are using so that I can further advise? And to clarify, you don’t need to actually delete the columns om mobile, you can just enter different widgets or remove widgets from this column.
I hope this helps!