The issue is that HATs go between the Pi and the PiDP-x (which itself is just a really big HAT). This HAT does not provide an extender for the GPIO pins, so the length of that would need to be calculated as well as part numbers for additional spacers.
I've had good luck with the Pimoroni NVMe Base, whic is an "anti-HAT" as it goes on the other side of the Pi and won't change the mounting of the Pi to the PDP-x.
In the PiDP-11, if you're using any of the rear panel cutouts the combination of Pi + Pimoroni NVMe Base sticks out enough that the rear panel may not seat properly. Fortunately, it is possible to open the Pi + NVMe Base like a book (see the attached picture) which has worked quite well for me.
Remember, both the official Pi NVMe HATs and the Pimoroni one need a
Raspberry Pi 5, as that's the first model to bring a PCIe lane out to a
dedicated connector.
