Urban IxD sounds interesting but scary at the same time if interventions are controlled by a private corp entities instead, for example an open cooperative.
Also as IxD inherently tries to control behaviour (indirectly), merging it with public spaces should be done very sparingly. There should be some spaces and areas in life where people should be allowed to just “be”, spaces for serendipty, exploration untouched by any subtle manipulation of artifacts.
Critical design is also quite interesting, although points raised by Ahmed Ansaari should be kept on in mind when considering it in the context of global south
https://www.media.mit.edu/videos/knotty-objects-2015-07-16-10/ (sorry this talk is not on critical design with respect to IxD, with software as a material but critical design as a paradigm in general)
I think if critical design if done in collaboration with anthropologists, sociologists and policy makers who are deeply immersed within the realities of their respective cities cultures and socioeconomic conditions it has great potential to spark creative capacity of the public.