These charts previously linked didn't help? https://www.kingarthurflour.com/learn/high-altitude-baking.html#cakes
Well here's CSU's book on the topic of cooking all sorts of stuff at atltitude. https://extension.colostate.edu/top...ty-health/high-altitude-food-preparation-p41/
Here is a rather scientific book on baking at high altitude https://babel.hathitrust.org/cgi/pt?id=uiug.30112019445920;view=1up;seq=9
Here's an old book developed in Denver CO (av elevation 5400 ft.) Doesn't give the why, just all sorts of recipes https://babel.hathitrust.org/cgi/pt?id=coo1.ark:/13960/t8v98qc7w;view=1up;seq=22;size=150
LD
How you work the biscuit dough can affect the final product dramatically. Over working the dough will will create too much gluten for a quick bread and it will be more like hardtack.
People who live at very high elevations like Tibet, cook most of their foods in a pressure cooker.