I think the OT will do what you want with relative ease. I find it a very easy machine to work with when I dedicate time to learning/remembering. If there are months between using it, it is easy to forget some things, but this is less of a problem with the Mk2 and it’s additional buttons - fewer obscure combos to remember.
Given the level of intensity you seem likely to apply to the OT, a Mk1 should be just fine. You should be able to sell it for what you paid if you don’t like it or want to have a Mk2 instead.
An interesting comparison. Pollock’s process is fairly transparent - there are videos or maybe just still photos of him dripping paint on canvases. You do need a paint or ink that is fluid enough to flow and drip and splatter, but I can’t recall if he even used brushes or just stir-sticks. RDJ on the other hand is far more opaque and varied. The OT does make it easy to produce material that could be considered IDM, but it can also do Eno-Fripp style looping and plenty of other experimental stuff.
OP should probably just buy an OT.