My point of view only but when I started again I use lot and got a rather unpredictable feel cornering and the car seems to be quite nose heavy on jumps (the car, even mid motor, didn't jump flat).
After asking here and there most don't use any to be able to control the feel in corners and the correct amount of steering braking produces.
Some others good drivers use some all the time as a part of their driving (around 10% for most).
So I put 0% and learn to drive (still am
). Once familiar with the track I try to put it back on and learn to control jumping accordingly. Found a small amount helps but on high speed corners I sometimes need some rolling at neutral and the tight once need some manual breaking action nevertheless.
Guess it's all about finding the good amount for a track that will help on most corners, with some rolling on high speeds ones and not too nose heavy on jumps.
Rear motors need more than mid. Almost no drag brake on dirt/low grip to control sliding and a little more than usual on carpet. Too much kills lap times.
I've got a lot of things to learn to manage still, from shocks to gearing, links, diff setting, etc and drag brake is a nice tool to adjust on the track to fine tune the way the car cornering feel/jumps.