This is all because dt is ICC profile based, which means it operates on the 0.0-1.0 range assumption. 1.0 here means “max value”, and for PQ this is an absolute 10000 nits. So you have to figure out where you want to place your “1.0” in terms of nits and exposure compensate accordingly.
HLG is more forgiving as it is relative and not absolute. I like to pull about 1 1/3 EV before exporting to HLG: Experimenting with HLG and HDR10 for still images - #15 by kmilos