Cell-site simulators (CSS)—also known as IMSI Catchers and Stingrays—are a tool that law enforcement and governments use to track the location of phones, intercept or disrupt communications, spy on foreign governments, or even install malware. Cell-site simulators are also used by criminals to send...
Not saying you’re wrong, but I’d love to read the sources to your claims.
Example: https://grapheneos.org/faq#baseband-isolation
Baseband modems were not isolated from kernel memory in stock Android, GrapheneOS had to do it themselves using the IOMMU. We do not know for sure due to the proprietary/closed-source nature of baseband modem drivers, but we have no reason to assume any OEM (Samsung, Xiaomi etc) implemented proper isolation of baseband modem and system memory.
That’d be a huge oversight on their part. Thanks for the clarification.