I’d try a different filter before I went too far.
It could also be an issue with a cracked/broken pick up tube/screen.
If it’s not the filter, drain the oil and fish around in the pan through the drain plug hole with something like a long thin screwdriver or a telescoping magnet to see if anything is rattling around in there.
What oil pump situation are you running?
Internal or external line?
If external, I have seen a problem with one of the external pump covers allowing the relief valve to travel too far, and get cocked in the bore....... stuck in the full bypass mode........ then you have little to no pressure.