Group Column Data, With Values (Bypassing Blanks)

For an eventual home in a SharePoint List and in turn, a PowerApp, I'm looking to combine the contents of potentially many columns (maybe hundreds of potentials) with only a few having values.

Given the fact that I'm not sure how many columns I may stick the formula/code in to the 300th column (assuming the number of columns caps well under 300).  I'm less concerned about exactly where as I can copy and paste code in to whatever column.  I'm just clueless on the actual formula/macro.

From there, I would import the excel to a SharePoint List and eventually pull data from a dropdown in a PowerApp.

I've attached a file for reference.

Any insight would be appreciated.