Decent rear seat cover

Has anyone ever seen a rear seat cover that is solid on the bottom, but still allows the split seat to work the way it was intended and maybe have access to the arm rest once in a while? I’ve tried searching all over, but all I see is solid version and they all look loose. What I was hoping for is semi-custom / custom for '21 x3 that will kind of match the interior color, have the child seat installed over it and have a dog occupy the other side. The reason for split is because of the child seat that cover ain’t going nowhere, so if I need extra trunk space (obviously when the dog is not there), I want to be able to pull the seat back down.

Tried all the usual bimmer forums, but for some reason not finding anything like that in the US. Figured maybe someone here had experience. Any ideas?