In AR 2 & 3, as noted by PRSS, the brush head would always orientate itself dynamically to the direction of travel. (Though for it to work the pen needs to be sending back it’s rotational information to AR.) I miss spoke, at least in part, earlier and the Oil brush head’s orientation is indeed already locked to a Pens rotation as it moves. Oops, well this is embarrassing ! (note to self test before posting!) Well, same is the case with Artrage Vitae on iPad Pro with Apple Pencil. Does that mean the default oil brush head does not rotate ? In Artrage 6? Found one thread which was dealing with 'Custom Brush' with rotating head. I still have the old version of Artrage 2 on this machine.

So, since it is not an OS problem, what setting am I missing? Wacom Graphire Tablet too has the last updated driver. I use my Desktop with a 27 inch monitor only. And Huion K58 tablet too not a very old tablet. I also tried it out on my 9 month old Lenovo Laptop which has Windows 10 as OS, Core-i7, 24 GB RAM, Nvidia GTX 2060 graphics, with Huion K58 tablet. I am using Artrage on my Desktop with Windows 7-sp1 OS, Core-i7, 32 GB RAM, Nvidia GTX 1050Ti Graphic Card and with a Wacom Graphire 8'圆' pen tablet (13 years old). I am adding info that I missed in my post.

Autodesk sketchbook pro 7 rotate