Never heard of common cheap window blinds utilized as cheap substitutes having any positive impact as diffusers.
With reference to the following link - as just one sampler among the many - explaining the science and “do’s and don’ts of treating first reflections, and their educational breakdown the fundamentals of diffusion by outlining the different types of diffusion .... I doubt it.
https://www.gikacoustics.com/treating-first-reflections/
With reference to the following link - as just one sampler among the many - explaining the science and “do’s and don’ts of treating first reflections, and their educational breakdown the fundamentals of diffusion by outlining the different types of diffusion .... I doubt it.
https://www.gikacoustics.com/treating-first-reflections/