I just noticed that Amazon has a pair of camera backpacks that are back or side-loading!
Left one is side and back loading.
Right one is side and top loading.
These are direct links. I get no support from Amazon. I have not tried out these backpacks.
I just like knowing my options.
As with any product, these links can change or disappear by the time you read this, but you can search on Amazon for “camera backpack” and see what they have.