How about contacting Incase to ask if they will repair it? I have a Tom Bihn medium Cafe bag, and the clip broke. I emailed them about this some years later and they repaired it for me. After email discussion, I also ordered a “Freudian Slip” insert / organizer for it. This also fits in the original Ristretto which I got for my original iPad.
My two daily carry backpacks are a Swissgear for larger loads and a Booq which can carry a 15" MBP but has less internal space and forces me not to carry a heavy load. Sadly Booq went out of business and very few of their products are still available (https://sozodistributing.com/brands/Booq.html ).