@Mmarch
what oil and spec are you using?
did you only notice the oil press loss randomly 1 day or did it gradually get worse?
how many oil changes & filters have you gone through since it began happening? Tried using something different?
When you replaced the oil pump, you also replaced the pickup tube Oring?
if all of that checks out you can try heavier oil. Hard to believe you have bearing probs if the oil and air filter was replaced on schedule.