Mx13 centrifugal oil filter epa 10

Did my first oil change…OEM filters and seem to have lower oil pressure at idle. I know the process is to place filter in cap and then put it on. It must have fell off because I buggered the top bearing so I replaced cap with new. Waiting on a new lower bearing. Mine seems to be shot as it doesn’t thread on the base anymore. I’ve read that this can cause lower pressure so hopefully the new one I get takes care of it.
How does this issue cause lower pressure? Does the oil leak past not allowing proper pressure? Does this filter just filter and return back to sump…not feeding oil gallery? I can’t find a good schematic to understand this system. Thanks