D:OS1&2 do have full controller support. I don't know personally when they were added it games' lifespan.
I am sure that controller support is just a matter of time. Console ports are bound to happen, and Larian also showed interest in Steamdeck which will benefit greatly from full gamepad support.
I am looking at Stadia gameplay videos, and their UI didn't seem to evolve since day1 (perhaps someone with Stadia experience might comment - latest gameplay I found is from Patch7). Perhaps for PC they wait for finalized UI before implementing controller support that would work with new features, while Stadia got temporary, basic UI, as the platform demanded the feature 🤷‍♂️. Just making a guess.
