I want to learn how to manage in a potential future with extreme political suppression of communists / socialists, like making it impossible to work anywhere, arbitrary arrests, physical abuse, potential torture etc Are there any Marxists that wrote about that?
Read about the First Red Scare (1917-1920) and the Second Red Scare (1940s-1950s) in the US. Heavy suppression can be so subtle that most people don’t even notice. Trump is currently threatening to invoke the Sedition Act; most USans don’t even know what it is even though its been around for 100 years.