Oblivion runs fine after
The Digital Rights Management (DRM) software in this program
prevents it from running in CrossOver. If you are in a legal jurisdiction
which allows removal of such software, you may have luck running this
program. Unfortunately, CodeWeavers, because they are subject to the
Digital Millennium Copyright Act, will be unable to support you.
No other tweaks were needed.
The only problem are 1) the nearby ground in the out door scenes is blue-purple coloured and missing some detail as I recall from running Oblivion under Windows and 2) when in the Inventory screen where you should see a view of your character on the right there's just a black space.
2 I don't care about but #1 is a drag as wandering around outside is my favorite part of Oblivion.
I tried creating a Wine key in HKey_Current_User / Software and adding the following registry keys but has no effect:
"DirectDrawRenderer"="opengl"
"OffscreenRenderingMode"="fbo"
"UseGLSL"="enabled"
"VideoMemorySize"="512"
Some tips here suggest changing oblivion.ini. I don't have this file. Should I create it and if so where?