The overview (in DaVinci Resolve) is to grade in HDR Rec.2020, ST.2084(PQ), Analyse using Dolby to produce an SDR 100nit version, and finally export as SDR Rec.709.
I've no idea precisely what's going on in the 'black-box' of Dolby, (and unless you have the annual ££$$ license from Dolby, you can't access the trim controls) but tests have shown that in shots containing extreme dynamic range (see the Android Pop video posted above) something good happens to the treatment of highlights versus simply just grading all the way along in SDR Rec.709.
Basic flow:
1) Set your Resolve project up as above, with mastering and scopes set to 1000nits
2) Grade in HDR – push your extreme highlights [only] up to the 1000nit mark, pay attention to saturation
3) Use the Dolby controls to 'Analyse clip(s)' at the selected SDR level from the drop-down e.g. SDR 1886 Rec.709 100nits
4) Check the results with the 'tone mapping preview' ON
5) If the Dolby Gods have willed it, there will be enhanced 'detail' and colour in the highlight roll-off
6) Export the clip in the Delivery tab as Rec.709/2.4 or Rec.709-A if on Apple device, and select the Dolby tone-mapping preview from the bottom of the Advanced controls.
Your mileage may vary…!