Echo chambers and filter bubble are largely just a figment of the minds of political pundits

Echo chambers, filter bubbles, and polarisation: a literature review. Amy Ross Arguedas et al. Reuters Institute for the Study of Journalism, Jan 19 2022. https://reutersinstitute.politics.ox.ac.uk/echo-chambers-filter-bubbles-and-polarisation-literature-review

Abstract: This literature review examines social scientific evidence regarding the existence, causes, and effects of online echo chambers in the context of concerns about digital platforms contributing to polarisation in our societies generally, and in relation to scientific topics, specifically. The scholarship suggests echo chambers are much less widespread than is commonly assumed, finds no support for the filter bubble hypothesis, and offers a mixed picture on polarisation and the role of news and media use in contributing to polarisation, especially given limited research outside of the United States. Evidence about echo chambers around public discussions of science is limited; however, research on science communication points to the important role of self-selection, elite cues, and small, highly active communities in shaping these debates. These findings are important as terms like echo chambers are widely used in public and policy debates, sometimes in disparate ways, and not always aligned with the evidence.

Check also other literature with references: Politically partisan left-right online news echo chambers are real, but only a minority of approximately 5% of internet news users inhabit them; the continued popularity of mainstream outlets often preclude the formation of large partisan echo chambers