https://www.sciencefocus.com/science/how-long-do-biodegradable-bags-take-to-decompose/
the bags aren’t always as environmentally friendly as they seem. They’re made from similar petrochemical-based materials to conventional plastic, only with compounds added that cause them to disintegrate gradually in the presence of light or oxygen. They often then degrade into a sludge of toxic chemicals.
Must admit when I was a child our dogs did their business at home and a shovel (regularly rinsed in disinfectant) was used and it went down the outside privvy.
Only on very long walks could they not contain themselves and we were taught to get them to open soil if possible and then find a stick to bury it so no one trod in it.
I know my daughters use bio bags but have no idea of their quality, they are bright young women though so fingers crossed.