The bolt. With the 90° adaptor you have an extra sealing surface under the head of the bolt, for a total of 3.
View attachment 1716217199
Without the adaptor you only have 2, the filter and the gasket under the plate.
I honestly don't give a crap about the rest of it. Plenty of magnum engines have gone 200k+ with the shorter filter. Hell I have 170k+ on the 5.9 in my Dakota. Not worried about it at all.