I suspect that you are aware though that interleave may be a necessity for your line if certain types of interference are present, and without interleave, performance may be reduced because of corrupted packets. I am not much help because I’m not familiar with these terms, but someone will probably recognise them.
As for interleave; I have 37ms or 48ms ping time, depending on which tester I use, and that is with interleave, but I am using mere ADSL2 at 3.0/0.5 Mbps sync rate not VDSL2 like yourself. Also geography adds delay too; I am in North West Scotland, 1000km from London and the light travel time over that distance plus number of hops adds to the time it takes to get to my ISP’s routers in London.