Thanks @ThinhDinh. The sample from @MegannLock does calculate the minimum value across the set of columns. It also “replicates down” as new rows are added. It’s very smart. Thanks @MegannLock.
However I have three “reservations”. Firstly, whilst it very cleverly finds the min value it doesn’t identify the specific column holding that value. Secondly, I just don’t understand it, and I am always wary of introducing functionality into my apps that I don’t fully understand. Thirdly I would have loved to achieve this 100% in Glide.
So I guess I need to learn about Google Sheets QUERY to overcome two of these at least. Awesome community guys, yet again.