These are kind-of sort-of not really new ways of defeating rogue base stations. Just let the end-users decide if they want to allow any connectivity under 4G or not - that will solve most of these problems.

Basically, phones will connect using the highest-level standard (5G) and encryption standards that it can get a good connection with. Only under very degraded conditions will a phone even think of switching from 5G to 4G or 3G. I'm not sure any new phones. sold in the US at least, support 3G any longer, and 2G should definitely be out.

Kind of outdated at this point, but the lower the standard, the older and generally weaker the communications and encryption protocols are. Thus, if an attacker can degrade the 5G and 4G spectrum enough to make it almost unusable or otherwise advertise massively better quality of service metrics for their imposter station, a mobile device may switch to 3G, and thus use the attacker's base station to pass traffic through. The attacker may be able to break into the 3G packets and get into the internals of your communications easier than something like 4G or 5G.