It might be worth trying a new oil pressure sensor ... I don't think they cost much.I’m not certain, but what I’ve inferred is that the ECM knows what pressure to expect at certain conditions and when it is sufficiently outside of the expected value, the p0521 code triggers.
I’ve replaced the filter and screen twice - once in June and the second in November - each time with OEM. It seems unlikely to me that each of the new ones would have gone bad that fast.
Did you also record and compare oil pressure with the mechanical gauge with different oil filters?