Am I too late to this thread. If you do not need the map or GPS in general, Sigma 23.16 will do:
https://www.sigmasport.com/en/produk...less/bc2316sts It will record elevation profile and other relevant data. You can switch off the cadence and HR sensors.
There is even more basic Sigma 14.16:
https://www.sigmasport.com/en/produk...less/bc1416sts It also has altitude/gradient. I am not sure if it will record the elevation/speed profile.