I don´t know if PL6 is faster than PL5 for DP but processing speed and the differences between DP and DPXD is similar for your and my system.
I clocked a couple of example files (24MP)
DPXD 7 sek
DP 3 sek
DPXD 8 sek
DP 4 sek
DPXD in my case is around two times slower.
I have an i7 with 16 GB, SSD and Geforce RTX 3060 TI plus OpenCL active.
I wonder if somebody with a fast computer have tried if performance will increase if you increase the number of parallel processes from default 2 to something else.
Also take in account that there might be some problems with artefacts using XD. XD might not be the obvious choice of that reason. Please look at this link and the screen captures in it:
DxO PL5 vs DxO PL6 NR algorithm - DxO PhotoLab / DxO PhotoLab Mac - DxO Forums
Maybe DXO has released XD a little bit too early, because it might need some tuning before it´s fool proof.