Filter bubbles are more pernicious than that because even if someone has a large and diverse social network, search algorithms can shoehorn them into a smaller bubble where it's much harder to get a diverse set of honest information when a viewpoint is challenged by that social network. It's an orthogonal concern to social bubbles unless that individual doesn't use search engines to consume content, instead getting it all curated through a facebook feed or similar.

For example, a borderline far right extremist might consume a bunch of OAN and Breitbart type sources so the search engines begin to cater their results for that demographic. When a sudden event happens like the Capitol riots, their results might look like a bunch of Q conspiracy crap when they search for "capitol riot" instead of more honest media sources that might be enough to do a self-deprogramming (I'm not sure if filter bubbles have become so extreme, just throwing out a hypothetical). Even if they have a bunch of friends respectfully pointing out the faults in their logic, the filter bubble might make it impossible to do the independent research that would cement a reversal.