Do you have any comparison images? No Filter / Soften / VRayLanczos ?
I woul dlike to see the difference. I could make a test myself but my hope is that you have some images of your test still in the history
In my experience “Quadratic” or “Cubic” works really well, too. Quadratic in most cases, Cubic only when you have large images where the softening effect diminishes.
but in this test the sharpness/softness , render time was the target. so you can not see the highlight behavior. If you have time we all appreciate any further test. but if you have not the time I maybe do another test with targeting highlight behavior in weekend.