If you don't have the bandwidth to process all the arguments you're receiving... receive fewer arguments. Get involved in fewer shitposting threads on the internet. Have fewer arguments about politics at work. The solution is not to assume / reduce / summarize until the arguments become tidy little things you can stick in boxes, it is to just reduce your workload so that you can give the arguments you care most about the attention they deserve.
Likewise, you talk about devoting your attention to the most important arguments -- but how do you decide which arguments deserve that attention? You can't be doing that 100% independently, you must at some point be allowing other people to raise issues to your attention, and to shift your priors a bit by virtue of the credibility they have earned via their track record (of being right, of being honest, of caring about things you care about).