I told you, you're the car master and I'm anything but...
I'm pretty sure that changing the oil pump will not solve anything, but my mechanic tells me that his solution with Suzuki Swift filter (allows higher pressure), Audi A4/Passat oil filter housing 06B115417F (it may have the regulator and that's why he is using it), 1.8T oil pump and balance shaft delete works and that I should've bought the OEM oil pump. So I just want to take this out of consideration. He will also check everything again . I'm now thinking that the oil pump might be too week for the extra radiator.
Because this is happening only when the oil is super hot and I'm on cooldown lap under 2000 rpms, I'll change again the oil from Motul 15W-50 to even thicker Millers CFS 10W-60 NT+, maybe it will help.